11 Creepy Freshwater Aquarium Fish to Keep at Home

creepy freshwater aquarium fish

Can you name any creepy freshwater aquarium fish? Below are eleven that you might recognize whether you have them in your own tank or have seen them while out shopping.

Silver Arowana (Osteoglossum bicirrhosum)

You may be familiar with this name, given how popular a fish this is in freshwater aquariums. They live for up to fifteen years, grow up to three feet in captivity, and are a fairly aggressive species, which makes them a challenging pet.

If you own the Silver Arowana (AKA Dragon Fish), you will likely know how important it is to set them up in a large tank that will accommodate their size and mimic their natural habitat. Otherwise, the fish will suffer, either through stress, developmental issues, or even jumping out of the tank!

Would you be able to distinguish a Silver Arowana from other fish species just by sight? The most defining characteristic of this fish is actually its fins. Keep an eye out for a small tail fin with dorsal and anal fins stretching all the way down to it on a long, slender body.

Scientific Name:Osteoglossum Bicirrhosum
Common Name:Silver Arowana, Dragon Fish
Origin:South America
Max Size:9 inches (23 cm)
Lifespan:15 years
pH:5 to 7.5
Temperature:75 to 82 F (24 to 28 C)
KH: 1 to 8 dKH
Tank Size (Minimum)250 gallons

Axolotl (Ambystoma mexicanum)

This creepy freshwater aquarium fish isn’t technically a fish but an amphibian that is closely related to the Tiger Salamander! It is also verging on becoming extinct as of 2020 and is currently listed as critically endangered.

Appearance wise, it is clear to see that these species are amphibians instead of fish due to their external gills and the small arms protruding from their bodies.

An Axolotl actually requires a mix of fresh and saltwater in their tanks, known as brackish water, so you need to be comfortable setting up an aquarium of this type. In fact, they require a completely specific water recipe in order to survive! That’s why it is not recommended for beginner aquarists.

Axolotls are prone to many health concerns, including floating syndrome and various skin diseases that are sometimes difficult to treat. These have contributed to them becoming endangered.

Scientific Name:Ambystoma mexicanum
Common Name:Axolotl, Mexican walking fish
Origin:North America
Size:6 to18 inches (over 12 inches is rare)
Lifespan:15 years
pH:6.5 to 7.5
Temperature:60 to 64 F (16 to 18 C)
KH: 7 to 8 dKH
Tank Size (Minimum)20 gallons

African Freshwater Pipefish (Enneacampus ansorgii)

African Freshwater Pipefish (Enneacampus Ansorgii)
Photo: Aquamike

Also known as Dwarf Red Snout, this fish is incredibly rare in most aquariums and is very high maintenance when they are in captivity. Though many would recognize them due to their bright colors.

They are quite a curious species, so it is likely that if you are lucky enough to see some of the ones kept in captivity that there will be plenty of plants in the tank with them. But you will not see them mixing with other species when in their tanks unless it is snails, as they are very slow eaters!

African Freshwater Pipefish are also commonly bred in captivity instead of being caught and then sold on. This is because it is more difficult to care for a member of this species that has come from the wild.

Scientific Name:Enneacampus ansorgii
Common Name:Freshwater Pipefish, Dwarf Red Snout
Max Size:5 inches (13 cm)
pH:6.8 to 7.8
Temperature:78 to 82 F (26 to 28 C)
KH: 10 to 18 dKH
Diet:Carnivorous (tiny live foods)
Tank Size (Minimum)20 gallons

African Butterflyfish (Pantodon buchholzi)

African Butterflyfish (Pantodon Buchholzi)

The appearance of this fish is what makes them stand out and is the reason for their name. The African or Freshwater Butterflyfish is named due to its large fins looking like a butterfly’s wings when they are being studied from the surface.

The African Butterflyfish is very unique in how it moves as it can glide along the surface of the water instead of surviving below the waterline like the majority of fish. Due to their “wings” (fins), they are able to fly!

This species, like the African Freshwater Pipefish, enjoy having lots of aquatic plants as they like to hide in them. Just make sure that there is enough space for them to swim along the top of the tank.

Scientific Name:Pantodon Buchholzi
Common Name:freshwater butterflyfish, African butterflyfish
Origin:West Africa
Max Size:5.1 inches (13 cm)
Lifespan:5 years
pH:6.5 to 7
Temperature:73 to 86 F (23 to 30 C)
KH: 1 to 10 dKH
Tank Size (Minimum)40 gallons

Ropefish (Erpetoichthys calabaricus)

Ropefish (Erpetoichthys Calabaricus)

Make sure that you don’t get this creepy freshwater aquarium fish confused with an eel. It is very similar in appearance as it has a long, thin body without a ventral fin. They are also possibly the easiest fish to care for on this list, so perfect if you are only beginning your aquarium.

If you are good to your fish and provide it with the best habitat, the Ropefish (or Reedfish) can survive up to 20 years! So, make sure that there are lots of rocks to provide them with plenty of hiding spaces, as well as vegetation that is likely to be found in their habitat in the wild.

Did you know that this fish also has lungs? Because of its relation to the Polypteridae family, Ropefish actually have lungs that help them to survive when the water quality isn’t good, by surfacing and breathing in some air.

Scientific Name:Erpetoichthys Calabaricus
Common Name:reedfish, ropefish, snakefish
Origin:West and Central Africa
Max Size:16 inches (40 cm)
Lifespan:15 to 20 years
pH:6.0 to 7.5
Temperature:73 to 86 F (23 to 30 C)
KH: 5 to 20 dKH
Tank Size (Minimum)50 gallons

Black Ghost Knife Fish (Apteronotus albifrons)

Black Ghost Knife Fish (Apteronotus Albifrons)
Photo: dudlik

Another fish in this list that has a fairly distinct appearance is the Black Ghost Knife Fish. As you can probably guess from its name, this fish is actually shaped slightly like a knife with a slight curve to its thin form. It also doesn’t have any fins! Simply a small ridge where the fin usually would be.

Did you know that this is another fish that is mainly bred in captivity? Due to its popularity, the Black Ghost Knife Fish has been bred in captivity for years now, and it is far more likely that the ones you are seeing have never been in the wild before.

When preparing to care for a member of this species, remember to fill the tank with things reminiscent of their habitat; rocks, plants, logs, etc. A softer substance like sand on the bottom is crucial as this is where they will spend the majority of their time.

Scientific Name:Apteronotus albifrons
Common Name:Black ghost knife fish, BGK
Origin:South America
Size:14 to 18 inches (35 to 45 cm)
Lifespan:up to 10 years
pH:6.5 to 8.0
Temperature:75 to 82 F (24 to 28 C)
KH: 5 to 10 dKH
Tank Size (Minimum)120 gallons

Ornate Bichir (Polypterus Ornatipinnis)

Ornate Bichir (Polypterus Ornatipinnis)

This stunning fish is sometimes referred to as the “dinosaur eel.” It can be easily distinguished by its unique black and gold pattern.

If you already have some fish in the tank that you are hoping to put the Ornate Bichir in, it is important to remember that it will eat any fish that it considers to be small enough to be prey, even if it isn’t naturally aggressive species.

Something important to remember is that this fish likes to jump. Make sure that you have a close-fitting lid that will also allow it to breathe air from time to time, or it just might jump out!

Scientific Name:Polypterus Ornatipinnis
Common Name:Ornate Bichir
Origin:West Africa
Size:24 inches (60cm) (18 inches on average in the aquarium)
Lifespan:up to 15 years
pH:6.5 to 7.5
Temperature:77 to 83 F (25 to 28 C)
KH: 1 to 10 dKH
Tank Size (Minimum)180 gallons

Amazon Leaf Fish (Monocirrhus Polyacanthus)

Amazon Leaf Fish (Monocirrhus Polyacanthus)

Can you guess what this fish looks like? You guessed right, a dead leaf! Its yellow or brown colorings and spiny fins help it to blend in with the debris on the waterbed.

It isn’t a fish that would do well sharing a tank with other species as it lies in wait for its food, so it is likely to eat any others in its space if they view them as prey.

The Amazon Leaf Fish prefers dimly lit habitats with plenty of driftwood and other objects that it can camouflage itself amongst. So, it is important that you provide them with plenty in the tank.

Scientific Name:Monocirrhus Polyacanthus
Common Name:South American Leaffish, or Amazon Leaffish
Origin:South American
Size:3 to 4 inches (7.6 to 10.1 cm)
Lifespan:5 to 8 years
pH:6.0 to 6.5
Temperature:77 to 82 F (25 to 28 C)
KH: 2 to 5 dKH
Tank Size (Minimum)20 gallons

Freshwater Sole (Brachirus Selheimi)

Freshwater Sole (Brachirus Selheimi)
Photo: Ryan Francis

The Freshwater Sole is quite small in comparison to the other fish in this list, reaching roughly five inches when fully mature. Their bodies are also flat and blend into the sand that is lying on the floor.

They eat smaller fish but should be alright in a tank with larger species so long as the others aren’t too aggressive or likely to beat them to the food source continuously.

Scientific Name:Brachirus Selheimi
Common Name:Freshwater Sole, Freshwater Flounder
Size:5 inches (13 cm)
Lifespan:up to 15 years
pH:7.0 to 8.1
Temperature:76 to 82 F (24 to 28 C)
KH: 7 to 10 dKH
Tank Size (Minimum)55 gallons

Freshwater Lionfish (Batrachomoeus Trispinosus)

Freshwater Lionfish

Have you ever seen a fish that was covered in spines? Well, this one is. The Freshwater Lionfish have spines covering its flattened body; although they aren’t venomous, they will hurt if you prick your finger on them!

To match its habitat, it is best to supply this fish with plenty of items they can use with their camouflage on the bottom of the tank because this is where they will spend most of their time. Also, make sure to get a large tank since they can become very big!

Like the Axolotl, the Freshwater Lionfish likes to have brackish water instead of freshwater, so make sure to have this in the tank for this toadfish relative.

Scientific Name:Batrachomoeus Trispinosus
Common Name:Freshwater Lionfish, Freshwater Stonefish, Three-spined Frogfish, Toadfish
Size:11.8 inches (29.97 cm)
Lifespan:up to 15 years
pH:7.5 to 8.5
Temperature:72.0 to 82.0° F (22.2 to 27.8° C)
KH: 7 to 10 dKH
Tank Size (Minimum)100 gallons

Freshwater Frogfish (Antennarius Biocellatus)

There is no specific coloring that identifies this fish; however, it is rather angular, with an eyespot or two on its dorsal fin. 

Freshwater Frogfish prefer brackish water but can also be found in freshwater. If you are looking into keeping one, then it is important to keep the salt level minimal to ensure they have the best chance of survival.

The slow-moving fish are another on this list that likes to wait until their prey approaches them. As they move slowly, it is best to keep them separate from any fish that may reach the food supply before them.

Scientific Name:Antennarius Biocellatus
Common Name:Freshwater Frogfish, brackish-water frogfish, the fishing frog
Size:5.5 inches (14 cm)
Lifespan:up to 15 years
pH:7.0 to 8.2
Temperature:76 to 82 F (24.4 to 27.8° C)
Salinity: 0 – 35ppt
Tank Size (Minimum)40 gallons

Final Thoughts

If you are looking to purchase one of these creepy freshwater aquarium fish, here are some things to keep in mind:

  • Whether they prefer freshwater or brackish water.
  • How they prefer their environment.
  • How big they will grow as an adult.
  • Whether they interact well with others.

The fish listed here may have some similarities, but they are all unique in their own ways and require attention to different areas.

Do you have any other creepy freshwater aquarium fish that you would like to share? Let us know in the comments section below!

Black Wolf Fish (Hoplias curupira): Fish Species Profile

Black wolf fish(Hoplias curupira)

If you’ve been around the hobby long enough, chances are you have already owned most of the common aquarium fish sale at pet stores.

Keeping some of the fiercest predators is probably a great next step for expanding your aquatic species collection and enriching your fish keeping skills and knowledge.

Black wolf fish is the perfect candidate for that. 

This guide will go over everything you need to know about black wolf fish, from their behavior and diet in the wild to what it takes to keep them healthy in captivity. 

Species Summary

The black wolf fish (Hoplias curupira) is a predatory species native to the Amazon River, and several of its major tributaries stretched across northern regions of South America.

It is named after a creature from Brazilian mythology, the ‘curupira,’ famed for protecting the forest and seeking revenge on those who bring harm to it. The comparison is apt for such an antagonistic species.

Black wolf fish are related to the various other species of wolf fish found all over South America and are able to survive in fairly difficult circumstances due to the fact that they can, surprisingly, breathe air; after a long drought, it’s not unusual for a hardy wolf fish to be the last survivor in a rapidly depleting mud pool. 

Furthermore, Hoplias really do deserve their name. They are generally all extremely territorial and capable of being highly aggressive. The black wolf fish is no exception, though this doesn’t mean that they are not suitable for the well-prepared fish keeper’s aquarium. 

Scientific Name:Hoplias curupira
Common Name:Black Wolf Fish
Origin:the north of South America
Size:16 inches (40cm)
Lifespan:At least 15 years
pH:6.0 to 7.5
Temperature:74 to 86° F (23 to 30° C)
KH: 0 – 5 dGH
Tank Size:120 gallons (48″ x 24″ x 24″)

What Does a Black Wolf Fish Look Like?

Black wolf fish are relatively thick-bodied, especially in relation to other members of the Hoplias genus. They have a blunt, round-shaped head which is especially noticeable when viewed from above, and a prominent, elongated dorsal fin that fans out prominently when the fish is agitated. Their eyes are small and dark and are sometimes difficult to distinguish.

In terms of coloration, they have a sandy brown and black flecked appearance, perfect for camouflaging themselves when approaching prey in a sandy Amazonian riverbed.

Their shading, however, can alter depending on the mood of the fish, moving from a light yellowish brown to a much darker hue of near black (giving the fish its common name of black wolf fish). 

Most specimens will also display a thick dark stripe, which is occasionally outlined with lighter-colored scales, running along the flank of the fish from the tail to its rather prominent gills. 

Last but not least, black wolf fish have a number of rows of razor-sharp teeth. Be sure to never let your fingers get too near them!

How Long Do Black Wolf Fish Live?

The black wolf fish was first formally described in 2009 – a fairly new addition to the aquarium hobby. There is not much information regarding its lifespan, but it is estimated that it can live at least 15 years, so a prospective owner must make a long-term commitment to fulfilling the needs of a black wolf fish.

Size & Growth Rate

Like most Hoplias species, black wolf fish can grow to quite a size, though they are in no means the largest of the wolffish. 

Author note: The Gold Wolf Fish (Hoplerythrinus unitaeniatus) is the smallest wolffish, reaching just over 8 inches (20 cm).

Black wolf fish kept in home aquariums tend to grow smaller and usually grow no larger than 16 inches (40cm), while wild specimens have been known to reach up to 30 inches (75 cm) in length. 

However, this happens at an extremely fast rate, with younger specimens growing by an inch per month, depending on how much you feed them.

Black Wolf Fish Care Guide

As has been mentioned, the wolffish family is generally quite aggressive, and the black wolf fish is no exception. 

It has often been remarked that piranha is actually quite shy and passive compared to wolffish, so that should give you an idea of what we are talking about here.

This is reflected in their behavior toward other fish and even towards the owner. In fact, it is not unusual for poorly prepared owners to receive a nasty bite or for black wolf fish to be observed charging the aquarium glass or any contraption being used to ensnare them.  

For these reasons, black wolf fish tend to be kept alone, although it is possible for them to be kept with other large fish which will not challenge them territorially (or fit in their mouth). Appropriate choices may be larger members of the cichlid family or characins of a similar size.

Tank Size

For this large fish, your tank should really be a minimum of 120 gallons (48″ x 24″ x 24″) though you may wish to consider an even larger aquarium, especially if you decide to house the fish with other tank mates.

Larger tanks with big footprints are generally considered better, so height is less important than the width in this case. The larger the aquarium, the more likely they will swim rather than hover in mid-water.

Crucially, the tanks must have a strong, tight-fitting lid because these fish are extremely good jumpers and will manage to get out of an aquarium if given a chance once too often.

Water Parameters

Like most fish from the Amazon, their habitats are often surrounded by quite dense plants.

As fruits, leaves, and branches that fall into the water decay, they leach tannins into the water, creating a soft, acidic environment to which black wolffish have grown accustomed. They are not picky, but extremes should be avoided.

Ideally, aquarium water should have a pH value of between 6.0 and 7.5 and be soft (with a general hardness of around 0-5 dGH). Temperature-wise these fish are not too sensitive, but anywhere between 74 to 86° F (23 to 30° C) will be fine. 

Décor (Plants and Substrate)

In their natural environment, black wolf fish are found in relatively open waters with moderate water movement.

The aquarium can be fairly plain, but it is a good idea to recreate this by providing plenty of open space with natural-looking bogwood and roots for them to hide in.

Any plants (live or artificial) and bogwood that are used must be robust enough to withstand an occasional fly past by these lively predators. A dark-colored substrate of either sand or gravel will make this fish feel at home. 

Behavior & Temperament

Black wolf fish (H. curupira) are notoriously aggressive and will be a threat to any smaller tank mates, who may be eaten whole. When they want to, black wolf fish can move extremely quickly, meaning the fish keeper must exercise caution when performing maintenance. 

Aside from being a threat to other fish and the keeper, black wolf fish have even been known to attack filtration systems and any device used to trap them. Ensure your equipment is securely in place.

Black Wolffish Tank Mates

This aggressive nature and full-grown size make it difficult for many tank mates to live alongside black wolf fish. The only species that can truly be considered safe are larger, robust fish of similar size and temperament, such as other wolffish relatives or large SA & CA cichlids.

However, there’s always the caveat that Black Wolf Fish might decide to attack them anyway, even larger fish. There are also rumors of these fish peacefully co-existing with Stingrays, Arowanas, Brycons, Dorados and peacock bass, but it’s far from guaranteed.

Food & Diet

In the wild, these predators will spend the majority of their time hunting down smaller fish and large insects, and so, for this reason, live food is preferred. They will appreciate foods like worms, feeder guppies or goldfish, crawfish, and silversides. 

However, over time they can be trained to eat frozen food and frozen food such as shrimp and mussels. They need to be fed regularly, at least two times per day.

Furthermore, these fish are generally less active in the day and more active at night; this is why you should feed them before you go to bed.


Breeding black wolf fish is not known in captivity, but it may follow a similar pattern to other Hoplias species.

The biggest challenge is having a bonded pair of a similar size because the larger one will also try to attack the smaller one.

Most Hoplias members are very prolific and will spawn in pairs, with the female laying as many as 10,000 eggs. Therefore, a very large breeding tank of at least 400 gallons is required.

What’s more, the fry are difficult to raise and must be sorted according to size as they grow to prevent the smaller ones from being killed and eaten by their larger siblings.


Although black wolffish are not widely available, they can be found in specialist online stores and aquarist societies. Usually, they come with a very high price tag.

Be sure of what you are getting, though, as they are often sold as the most kept species: Hoplias malabaricus, which is much larger and requires a larger territory.

Bottom Line

For any keepers interested in predatory fish, black wolf fish should definitely be on your radar. Watching them feed can be a thrilling experience and will definitely make a good video clip for your social media. 

However, it is important that they be housed in a large enough tank and be matched with fish big enough to avoid a sticky end. 

Have any anecdotes that you’d like to share? Let us know in the comments!

Crocodile Toothpick Fish Species Profile: Size, Diet, Tank Mates & More

Crocodile Toothpick Fish (Indostomus crocodilus)

Observing the behavior of crocodile toothpick fish can be both calming and rivetting. They’re slow, quiet, and tranquil in nature. They’re also remarkably curious fish, making them a joy to watch. 

This post includes all of the information about the crocodile toothpick fish that you need to know. This includes details on the tank size, food, water parameters, substrate, and more. 

By the end, you’ll be feeling more assured about what a crocodile toothpick is and how to properly care for it. 

Species Overview 

The crocodile toothpick fish, scientifically known as Indostomus Crocodilus, is an incredibly small fish that originates from Southeast Asia, where they reside in still freshwater. They’re commonly found throughout the southern regions of Thailand, but you can also find them in Peninsular Malaysia. 

Indostomus is a small group of fish consisting of only three recognized species, including I. crocodilus, I. paradoxus, and I. spinosus.

These fish are small and fragile, so those new to aquariums may struggle to keep groups of crocodile toothpick fish alive. They can’t swim so well either, meaning that more care and attention are needed. 

Therefore, it’s best for people with more experience with caring for fish to consider adding crocodile toothpick fish to their aquariums.

Scientific Name:Indostomus Crocodilus
Common Name:Crocodile toothpick fish
Origin:Southeast Asia
Size:1.2 inches (3 cm)
Lifespan:3 – 5 years
pH:5 to 7
Temperature:72 to 27 F (22 to 80 C)
KH: 0 – 5 dKH
Tank Size:5 Gallon


Indostomus Crocodilus (crocodile toothpick fish)

The crocodile toothpick fish is aptly named for its slender body with a crocodile-like head, tapering off to a fan-shaped tail. 

They are often mistaken for the toothpick fish (Vandellia cirrhosa) from the Amazon and pipefishes (Microphis spp.) due to their similar appearance.

The ventral, anal, and dorsal fins of male crocodile fish are accompanied by white seams. Males also have pelvic fins that curve inwards. In females, these pelvic fins are slimmer and straight. 

Female crocodile toothpick fish can easily be distinguished from males during breeding [1]. This is because their abdomens become increasingly large and rounded. The breeding process between males and females often happens in bamboo or other tubular aquatic environments. 

Males have black stripes on their fins and also show strong signs of guarding early on, which is a behavioral difference compared to females. 

Maximum Size 

The small size of crocodile toothpick fish is one of the main factors to consider when you’re thinking about keeping them in an aquarium. 

They only grow to 1.2 inches (3 cm) in length and remain fragile throughout their lifespan. As a result, extra care and attention are needed when caring for these fish. 

Crocodile Toothpick Fish Care 

In terms of their care, crocodile toothpick fish need the right tank setup and environment to stay healthy and thrive. This includes lots of swimming space, comfortable water parameters, and plenty of hiding spots.

However, if the idea of a challenge excites you, here’s what you need to know about caring for these fish. 

Tank Size

Tank size is one of the main challenges that people face when keeping a new species of fish. 

The ideal tank size for single crocodile toothpick fish is 5-10 gallons because of their petite size and low bioload. They are not school fish but a curious species, look better and display more interesting behaviors if you get groups of at least a half-dozen or more and put them against a lush plant background.

So, if you have multiple crocodile toothpick fish, you’ll need to expand this space accordingly. Add 5-10 gallons per extra fish.

Water Parameters

These fish can thrive in waters that are anywhere between 72 and 80 Fahrenheit. This provides you with a good range to choose from. 

In addition, the ph levels of the water should be 6.0-7.0, making it a marginally acidic environment which they prefer. You should aim for a water hardness of 0-99 ppm. 

You may also want to consider implementing a filter that increases the flow of water that provides 4-5 times the amount in your aquarium. This ensures that your fish get fresh water and are able to thrive. 

Decor (Plants and Substrate)

In their natural habitat, the Indostomus species prefer still freshwater. Therefore, they mostly reside in lakes, ponds, and streams. It’s also common to find them living near plants and algae. 

As mentioned above, it’s best to keep crocodile toothpick fish in a well-planted tank. Floating plants like duckweed and hornwort are good options for diffusing light. They will thank you as they prefer dimmer environments.

For substrate, a finer substrate material with decaying organic and plant matter, leaves, branches, and dirt is ideal. This will give them plenty of natural hiding spots and provide an aesthetic touch to your aquarium. 

These reclusive creatures are not often seen. They don’t startle easily, instead preferring to stay in the shadows until they feel it’s safe enough for them to explore their surroundings.

Oak leaves are recommended additions to the aquarium of crocodile toothpick fish, as they are known to contain tannins that aid in the health of your fish. Don’t overuse them, or your pH level will drop. A few leaves every few weeks is enough. 

Temperament & Tank Mates

Crocodile toothpick fish and corys
Photo: AquaMrs

Crocodile toothpick fish are towards the bottom of the food chain. Their small size makes them easy prey for large fish. 

It’s best to keep these fish alone or in a community tank with other peaceful fish or aquatic critters that are the same size. 

They aren’t too concerned with living in the same space as others of their species. Males sometimes become territorial towards rivals; However, they don’t cause harm to each other which is considerate of them.

One of the strange habits that they have involves swimming vertically. Some people become alarmed by this, but it’s pretty normal behavior for this species due to the way they perceive objects around them. 

Crocodile toothpick fish is more of a peaceful, curious species that simply enjoy hanging around the driftwood. Ideal tank mates for the black orchid betta include:

Food & Diet

A common mistake that people make is not feeding their crocodile fish. This is done based on the fact that these micro predators do not like prepared dried or frozen foods in the aquarium.

In the wild, crocodile toothpick fish primarily feed on tiny aquatic crustaceans, insect larvae, worms, and other zooplankton. However, things are different in an enclosed tank, even if there are plenty of plants and organic matter around. 

To mimic their natural diet, you should offer these fish small live foods such as daphnia, baby brine shrimp, nauplii, or micro worms.

In an established tank, naturally occurring macrofauna [2] that inhabits the soft substrate can also be an additional food source – another big plus when you have oak leaves at the bottom.


These fish are egg-layers. Breeding crocodile toothpick fish is possible, but it’s not easy since it’s a sort of rare fish in the hobby.

The best (or only) way to approach breeding this fish is to create a separate breeding tank with no less than 29 gallons. To ensure you have a bonded pair, start with a large breeding group of at least six individuals.

The tank should be heavily planted with plenty of driftwood and oak leaves so it has ample tiny microfauna and detritus for the fry to feed on.

Condition the adults with lots of high-quality proteins but avoid overfeeding.

Crocodile toothpick fish are sexually dimorphic. Males will have lighter bodies and bright dorsal and anal fins that are used to attract their female counterparts. When the male is ready, he will start to clean a spawning site and guard the area.

Spawning occurs near the entrance to the spawning site. Usually, males perform a variety of courtship rituals, such as erect fin displays, circling bouts, and quivering movements.

After spawning, the female will deposit as many as 40 eggs on the roof of the spawning site and then leaves the site. The male will protect the eggs until the fry become free-swimming.

Final Thoughts

Newbie aquarists may want to consider other types of fish first before deciding to keep crocodile toothpick fish. Their small size, fragility, and poor swimming abilities require the eye of a more seasoned aquarium owner. 

Owning these fish can be a fantastic experience due to how you can observe them exploring their curiosity. It can also be exciting to see how they react with other fish of the same species. 

If you’re still left with any questions about crocodile toothpick fish, please let us know! 

What Else Causes White Spots on Fish Other Than Ich? (11 Causes with Pics!)

white spots on fish not ich

If someone were to ask me what disease causes white spots on fish, my first thought would be Ich. After all, the main clinical sign of Ich is small white spots along the body of your fish.

However, there are other non-serious issues, and potential culprits can contribute to those pesky white spots appearing on your fish. 

For an effective treatment, it’s critical to make a confirmed diagnosis. Sometimes, you may want an aquatic veterinarian to examine your sick fish under the microscope and give you specific medications.

In this article, let’s talk about what else causes white spots on fish other than Ich and how you can address each issue.

Diagnosing Ich in Freshwater Fish

Ich (mistakenly pronounced as “ICK”), or white spot disease, is caused by a large, ciliated protozoan, Ichthyophthirius multifiliis. All species of freshwater fish, both wild and captive, are considered susceptible. 

Under a Microscope

In order to confirm a diagnosis of Ich in a freshwater fish, as we mentioned, your vet will look for the presence of Ichthyophthirius multifiliis in infected tissue under a compound microscope, even though it’s still not an easy task to make a quick determination because of the complicated life cycle of Ichthyophthirius multifiliis.

As with most aquarium parasitic diseases, it’s worth understanding this parasite’s entire life cycle. Not only can this help you identify the potential disease or point towards a different diagnosis, but it can also help you decide what kind of prevention and treatment strategies are appropriate for your fish.

Life Cycle of Ichthyophthirius multifiliis

Direct life cycle of Amyloodinium ocellatum.
Photo: ScienceDirect

Despite its direct life cycle (doesn’t require different hosts or a vector), it is fairly complex and composed of three distinct stages:

Feeding stage (Trophozoites)

At this stage, the free-swimming dinospores attach to the fish’s skin, fins, and gills, feeding off the tissue fluids and becoming nonmotile parasitic trophozoites

After three days to a week, the trophozoites mature into motile trophonts. The characteristic white spots of Ich are actually the tiny white capsule surrounding these mature trophonts, which measure 0.5 to 1.0 mm in diameter [1] and are visible to the naked eye.

The juvenile theronts are smaller, translucent, and spindle-shaped under the microscope. They look very similar to another ciliated protozoan called Tetrahymena (guppy disease). Therefore, it’s necessary to examine them closely until they reach maturity for a definitive diagnosis.

During this stage, both free-swimming dinospores and mature trophonts are covered by the fish’s epithelial tissue and mucus. As a result, the chemical treatments used in aquariums may be unable to penetrate the external shield of the parasite and be ineffective.

Replicating stage (Tomont)

Mature trophonts stop feeding and develop into tomonts. Some may leave the fish and drop off into the substrate or attach to plants and decoration, while others may remain on deep parts of the host’s tissue. 

No matter where they go, a tomont quickly secretes and forms a thick gelatinous outer cyst that allows it to stick to aquarium surfaces. Inside each cyst, the tomont begins to replicate and produce 250 to 1000 tomites [2] in a day at warmer water temperatures

The tomont and tomites are also protected by the cyst from the external environment and chemical treatments, which makes it difficult to eradicate at this point.

Free swimming stage (Tomites)
infective  "Ich" Tomites looking for fish host.
Free swimming Tomites (Photo: University of Florida)

The incubation period can be 3- 5 days. Then tomites are released from the cyst and become free-swimming, infective dinospores in the water column. They start seeking out a new host, and the cycle can begin all over again, but this time with exponentially higher numbers.

This is the only stage where chemical medication can be effective since these free-swimming tomites are unprotected, and they must find a live fish within 2 to 4 days [3] at warmer water temperatures of 75 to 79° F (24 to 26° C), or they may die. In cooler water temperatures, they can potentially survive nearly 30 days.

Without a Microscope

Ichthyophthirius multifiliis in betta fish
Ichthyophthirius multifiliis in betta fish

If you don’t have access to a microscope, you can diagnose it by closely observing the infected fish, including the physical signs and behavioral changes. 

Once infested, your fish may exhibit the following symptoms:

  • Rapid respiration: Because the gills are typically attacked before any other site, the early clinical signs are respiratory problems. You may see fish congregate around the areas of high oxygen content, such as filter outflows, powerheads, or air stones. Or even gasp for air at the surface.
  • Clamped fins: As a result of stressed fish, clamped fins may also be an early symptom.
  • Flashing: Fish often start scratching against objects in their environment. Signs like missing scales and trauma are indicators if you do not see this unusual behavior.
  • White spots: The classic sign of this Ich is the presence of small white spots the size of a grain of salt scattered on the fish. It’s more easily observed at thin, transparent fins or tails. Try to look at these areas in some lighter-colored fish from different angles to see them better.
  • Lethargy and loss of appetite: As the infestation progresses, your fish may become less active, eat less food and lose its coloration.
  • Sudden death: In some severe cases, death can occur in as little as 12 hours as the tomonts sometimes be deeply colonized in the guts or esophagi of a host fish.

Non-serious Issues

Although Ich is easily visible on the fish’s tail or fins in the early stages, it can be notoriously hard to diagnose once there’s lots of slime coat on its body. These tiny, salt-like crystals are easily confused with several non-serious issues, including: 

Stress Ich (Stress Spots)

Stress Ich Vs. Ich

First, stress is bad. Most common diseases in aquarium fish can be traced to stress as the primary factor that weakens the fish’s immune system. When a fish is stressed, it can develop these temporary white spots.

Diagnose (Stress Ich Vs. Ich): Unlike Ich, “stress spots” usually result from hormones caused by poor water quality, an improper diet, overcrowding, or aggression; thus, they are not contagious. Affected fish may show the same number of white spots daily, and there will be no exponential growth. For example, if there are five spots on the fish today, you will observe approximately the same amount tomorrow.

Treatment: Determine and eliminate any sources of stress.

Fin Ray Fracture

Various fish in the wild commonly have cartilaginous rays that support their dorsal and anal fins. Fin ray fractures or breaks occur when a fish is injured due to physical trauma, netting and handling, or even fighting with aggressive fish species.

Diagnose: Fin ray fractures produce localized swelling, appearing as tiny, irregular pinkish spots in the fin rays. Only one or two per fish are usually seen.

Treatment: In most cases, these fractures naturally heal by themselves [4] over time.

Breeding Tubercles on Male Goldfish and Koi

Breeding Tubercles on Male Goldfish vs Ich

When male goldfish and koi mature, they develop multiple white bumps on the face, body, and pectoral fins. It is a normal condition, and those spots are called breeding tubercles.

Diagnose: If you look closer, each spot has a sandpaper-like rough texture, unlike Ich’s smooth plastic feel.

Treatment: These breeding tubercles will only last during the fish’s breeding period.


Besides Ich (Ichthyophthirius multifiliis), several different parasites can cause white spots, including:

Guppy Disease (Tetrahymena)

Tetrahymena (guppy disease)

Guppy disease, often referred to as “guppy killer” among fish keepers, is caused by a group of ciliate protozoans called Tetrahymena. It can infect a wide range of fish species but is most commonly associated with guppies and other livebearers such as mollies and swordtails.

Diagnose: As mentioned above, Tetrahymena spp. often resemble juvenile theronts of I. multifiliis (Ich) with white spot-like cysts on the fish’s body and fins at the free-swimming stage. Therefore, it is nearly impossible to differentiate it from Ich without microscopic analysis.

Affected fish also show symptoms such as labored breathing, clamped fins, listlessness, and refusal to eat in the advanced stage of the disease.

In comparison to Ich, Tetrahymena spp. don’t need a live fish [5] to complete their life cycle, resulting in death much quicker. That could be why the fish died suddenly.

Treatment: Unfortunately, there is no reliable cure other than supportive care for Tetrahymena.


Epistylis, caused by the ciliated protozoa Epistylis spp., is a less-known disease affecting freshwater fish. Like Tetrahymena, it can be mistaken for Ich because of those little white spots on the eyes of this fish.

Epistylis species are a type of peritrich [6] with a rigid stalk; they usually form colonies and look like a Coral on the fish or other solid surfaces in the aquarium.

Diagnose (Epistylis Vs. Ich)

Identical in sizeVarying sizes
Visible whiteGreyish-white
Rarely appear on the eyesaffects eyes
Only white spotsForm white to gray irregular patches

Treatment: Formaldehyde (aka formalin) is considered an effective commercial chemical to treat and control the presence of protozoan ciliates. My experience has shown otherwise.

If Epistylis is severe enough, your fish may be susceptible to secondary bacterial infections. Making your own medicated foods with antibiotics, like Maracyn 2 and Kanaplex, is necessary.

Anchor Worms

Photo: Sunshine

Despite the name, anchor worms in fish are often referred to as Lernea species; they are not actually worms but a group of copepod parasites that attach themselves to their host fish using a hook-like structure on the front of their body and feed on the fish’s tissue.

Diagnose: You will see the female’s small, thin “thread” that resembles white worms hanging from the fish’s body. 

Treatment: Anchor worms can be removed manually by carefully pulling them off the fish with tweezers. Alternatively, a 30-minute bath in Diflubenzuron (also known as Dimilin) solution has been approved for Lernea treatment.

Bacterial Infection

Many bacterial infections in fish can manifest as white spots. Here are some of the most common ones:


columnaris in betta fish
Photo: Egggamethrowaway/Reddit

Columnaris, also known as cotton wool disease, cotton mouth disease, or saddleback disease, is a bacterial infection that affects the skin, fins, and gills of freshwater fish, particularly livebearers and catfish.

Flavobacterium columnare, a Gram-negative strictly aerobic bacterium, is the causative agent of Columnaris disease. 

Diagnose: The main clinical sign of Columnaris is white or grayish spots on the fish’s headfins, and gills. Many affected fish will develop cottony-looking lesions on their mouths along with the white patches. Another symptom is a characteristic “saddleback,” where the lesions usually have red edges on the back and often extend down the sides, hence the name.

Most fish suffering from a bacterial infection will “look okay”; they don’t rub or scratch against objects in the aquarium, but they look uncomfortable and listless, stay near the surface, or lay on the bottom of the tank, often with slightly clamped fins.

Treatment: Columnaris can be treated with a combination of Salt or Methylene blue (MB) bath and Nitrofurazone (Furan-2) based medicated food. For more details, read our step-by-step treatment here: Columnaris Treatment.

Fin Rot

fin rot in betta fish
Photo: otakme

Fin Rot is one of the most apparent symptoms of bacterial diseases in aquarium fish. Clinically, it’s caused by several anaerobic, gram-negative bacteria, including:

  • Aeromonas (anaerobic)
  • Pseudomonas (aerobic)
  • Streptobacillus (anaerobic)
  • Salmonella (anaerobic)
  • Vibrio (anaerobic)

Diagnose: As the name suggests, the primary clinical signs are frayed fin or tail. Depending on the level of infestation, the fin or tail may be completely disintegrated in life-threatening cases. It’s worth noting that these bacteria can affect other parts of your fish too. For example, black, white, or brown spots anywhere on a fish’s body may be observed.

Treatment: When your fish are at risk of illness, it’s important to investigate the cause before attempting to treat them. Testing the water quality should be the first step. If it fails, you should try to control and remove any possible stress factors in your aquarium before attempting a treatment.

Making your own medicated food by adding broad-spectrum antibiotics like Mardel Maracyn 2, SeaChem KanaPlex, or API Fin And Body Cure has been shown to be more effective against these gram-negative bacterial infections.

Canal Neuromast Syndrome

Canal neuromasts are specialized sensory cells found in the lateral line system of fish, which help fish detect vibrations, changes in water flow, and movements of other fish and prey.

Canal neuromast syndrome is commonly found in small cichlids [7], often presenting with small white spots on both sides of the fish’s head. 

Technically, it’s caused by a combination of the following issues: poor water quality, high bacteria count in the tank, internal parasites like Hexamita and Spironucleus,  as well as Mycobacterial Infections (aka Fish Tuberculosis). 

Diagnose: These bacteria and internal parasites can reside in the fish’s intestines or other internal organs and cause various symptoms, such as weight loss, erratic swimming, and lethargy.

Some parasites can also cause visible symptoms, like white dots protruding from the fish’s bodyThese fuzzy spots are about three times the size of Ich spots and exhibit identical patterns on both sides of the head or run along the base of the fish’s dorsal fin.

Treatment: To treat Canal Neuromast Syndrome in fish, improve water quality and upgrade filtration with good media first. In addition, dosing Seachem KanaPlex and MetroPlex in fish food should be part of your treatment plan.


fungus in fish

Fungus, also known as water mold or cotton mold, can lead to serious complications if left unchecked. The fungal pathogens are mainly from the genera: Saprolegnia, Achylia, and Branchiomyces. Several opportunistic species of Saprolegnia are responsible for the infection.

Diagnose: Saprolegnia, Columnaris, and Ich can often look alike, making them difficult to tell apart. Compared to the white spots of Ich, Saprolegnia spots tend to be bigger and fuzzier. If you want to learn more about how to differentiate between Columnaris and Saprolegnia, refer to our guide: Fungus Vs. Columnaris in Fish.

Treatment: Unlike bacteria, Saprolegnia spp. don’t respond well to these antibiotics. Don’t worry, there are various antifungal medications for fish available in the market. Acriflavine is effective against early stages, and Malachite Green or Sulfathiazole can be used for severe infections.

Viral Disease

Viruses are simple organisms that invade the fish’s cells and cause damage in the process. A few types of viruses can infect many freshwater and marine fish, but the most common one is lymphocystis.


lymphocystis in fish

Lymphocystis or Lymphocystis disease virus (LCDV) is a chronic disease caused by a DNA virus of the Iridoviridae family. This disease usually affects advanced fish, such as cichlids, killifishes, gouramies, clownfish, and many others, and is rarely seen in less-advanced fish, including catfish, goldfish, koi, barbs, or danios [8].

Diagnose: Generally, this disease is identified by the most obvious sign of small to moderate-sized, irregular, white bumps that can be mistaken for Ich. These growths may present in a cluster of dozens on the fish’s body, fins, and oral cavity. Without scraping and examining under a microscope, it is hard to distinguish this virus from Ich.

Treatment: There is no cure, but LCDV is a self-limiting disease, meaning these unsightly growths may appear over days in warmwater fish species and up to 6 weeks in coldwater fish.

Wrapping Up

As you can see, it’s not just Ich that causes white spots on fish. There are a variety of other issues that can lead to similar-looking symptoms, and proper diagnosis is key for successful treatment.

If you suspect your fish has white spots, start by doing a basic water quality test and observe the behavior of the infected fish. If you don’t see any improvement after a week, it may be time to consult a professional veterinarian. 

If you have any questions about white spots on fish or other fish health concerns, feel free to contact us; we’re more than happy to help you out.

References and Suggested Reading

  1. Ichthyophthirius multifiliis (White Spot) Infections in Fish [University of Florida]
  2. Ichthyophthirius multifiliis [sciencedirect]
  3. Aquarium Ich Disease | Ichthyophthirius Multifilis & Cryptocaryon in Fish [Americanaquariumproducts]
  4. Fin Ray Fractures in Messel Fishes [Kaupia: Darmstädter Beiträge zur Naturgeschichte 18]
  5. A Disease of Freshwater Fishes Caused by Tetrahymena corlissi [University of Nebraska]
  6. Peritrich [wikipedia]
  7. Spots on Head [AquariumScience]
  8. Lymphocystis Disease in Fish [University of Florida]

25 Best Fish for Your 10-Gallon Community Tank (Split by The Preferred Level)


A 10-gallon tank is popular amongst aquarists who are just starting out due to its compact size – virtually everyone can have one in their place.

From college dorms to nursing homes, tiniest apartments and even crowded classrooms, a nano aquarium is the perfect addition for those looking to add some fun and color in small spaces.

Unfortunately, the bad side of 10 gallons aquariums is that it can be challenging to find fish that are small enough to flourish in them.

That’s where this list will come in handy.

If you are planning to set up a 10-gallon community tank, here are 11 cool fish and critters that grow to suitable sizes and can make your mini underwater world come alive.

Any Level

There are quite a few species that are known for their vibrant colors, curiosity, and activity; they will likely move in all levels of the aquarium.

Upside Down Catfish (Synodontis nigriventris)

Upside Down Catfish (Synodontis nigriventris)

One of the smallest Synodontis species, the upside-down catfish (S. nigriventris ) gets its common name from its characteristic swimming patterns. Rather than swimming upright, this fish swims upside upside-down way!

These fish are not nano fish but can grow to 4 inches (10 cm) long and are best kept in small schools; However, you can still keep a single fish in a 10-gallon community tank even though it’s not recommended.

Scientific Name:Synodontis nigriventris
Common Name:Upside-down catfish, blotched upside-down catfish
Origin:Central Africa
Size:4 inches (20 cm)
Lifespan:5 years
pH:6 to 7.5
Temperature:72 to 79 F (22 to 26 C)
KH: 4 – 15 dKH
How Many Fish in A 10 Gallon Tank?Single/A Pair

White Clouds (Tanichthys albonubes)

White Clouds (Tanichthys albonubes)

This 1.5-inch (4 cm) minnow has a striking appearance because of its shimmering brown body, white belly, a prominent iridescent white lateral line with black shadows, as well as brilliant red tail started with a large black dot.

Like most minnows, this fish should be kept in a larger school, preferably of a half dozen or more. For a 10-gallon aquarium, no more than four White Clouds should be added. In addition, white clouds are a coldwater fish that do not require a heated tank.

Scientific Name:Tanichthys albonubes
Common Name:white cloud mountain fish, white cloud mountain minnow,Canton danio, Chinese danio, white clouds,
Size:1.5 inch (4 cm)
Lifespan:3 to 5 years
pH:6.0 to 8.0
Temperature:60 to 72 F (15 to 22 C)
KH: 5 to 19 dKH
How Many Fish in a 10 Gallon Tank?4

Zebra Danio (Danio rerio)

Zebra Danio (Danio rerio)
Photo: Alex Bell /instagram

Hailing from India, zebra danio is one of my all-time favorite small community fish, which can be easily identified by its distinctive horizontal stripes that run across its body.

These small but active fish can grow to about 2 inches (5 cm) in length and stay relatively peaceful when kept in a school of 4 or more individuals. They are easy to care for and prolific, making them ideal for first-time breeders.

Scientific Name:Danio rerio
Common Name:Striped danio, zebra danio, zebrafish
Size:2 inches (5 cm)
Lifespan:3 to 5 years
pH:6.5 to 7.0
Temperature:64 to 74 F (18 to 24 C)
KH: 5 to 12 dGH
How Many Fish in a 10 Gallon Tank?4

Top to Mid-dwelling Fish

The mid to top levels of the aquarium should be populated with vibrant, active fish to create a captivating focal point.

The most commonly kept mid to top species include:

Black Neon Tetra (Hyphessobrycon herbertaxelrodi)

Black Neon Tetra (Hyphessobrycon herbertaxelrodi)

Tetras, also known as characids, are the most colorful and lively options for the middle level of a community tank. Black Neon Tetras are a staple in the aquarium trade because of their pleasant personality and contrasting colors.

This schooling fish can grow to 1.5 inches (3 cm) in length and prefer to be kept in schools of six or more individuals. Consider keeping this energetic fish if you want to add a splash of vivid colors in your 10-gallon community aquarium with plenty of plants and a dark background.

Scientific Name:Hyphessobrycon herbertaxelrodi
Common Name:Black tetra, neon tetra, black neon
Size:1.5 inches (3 cm)
Lifespan:3 to 5 years
pH:5.5 to 7.5
Temperature:73 to 81 F (23 to 27 C)
KH: 0 to 6 dGH
How Many Fish in a 10 Gallon Tank?6

Green Neon Tetra (Paracheirodon simulans)

Green Neon Tetra (Paracheirodon simulans)

Smaller than the black neon tetra, this little beauty rarely is larger than 1 inch, making it suitable for a 10-gallon fish tank. It also sports a neon horizontal stripe along the sides but in brilliant blue and green.

Because of their petite size and blueish-green coloring, they look better if you get a school of five fish and put them against a darker background or a gorgeous background of lush green plants. They will move around in the top of your 10-gallon community tank, adding flashes of color and streaks of activity.

Scientific Name:Paracheirodon simulans
Common Name:Green Neon Tetra
Origin:South America
Size:1 inch (2.5 cm)
Lifespan:2 to 3 years
pH:7 to 7.5
Temperature:75 to 84 F (24 to 29 C)
KH: 4 to 7 dGH
How Many Fish in a 10 Gallon Tank?6

Harlequin Rasboras (Trigonostigma heteromorpha)

Harlequin Rasboras (Trigonostigma heteromorpha)
Photo: Zoo Braník/instagram

Like Neon Tetras, Harlequin Rasoboras or Red Rasboras are readily available everywhere. This 1.75 inches (4.5 cm) fish has a reddish body that is contrasted with a wedge-shaped black marking (as seen in the picture above), giving it an eye-catching harlequin appearance, hence the name.

Like most fish on this list, you will need to get a small school of at least five fish to best appreciate their beauty in a community tank. Live plants and driftwood are all welcome.

Scientific Name:Trigonostigma heteromorpha
Common Name:Red rasbora
Origin:Southeast Asia
Size:1.75 inches (4.5 cm)
Lifespan:up to 6 years
pH:6.0 to 7.5
Temperature:73 to 82 F (23 to 28 C)
KH: Up to 12 dGH
How Many Fish in a 10 Gallon Tank?5

Chili Rasboras (Boraras brigittae)

Chili Rasboras (Boraras brigittae)

Chili Rasboras, often referred to as Mosquito Rasboras, are a very peaceful species that make excellent candidates for any nano community tank with plenty of live aquarium plants.

These tiny, brightly colored rasboras stay around 0.5 inches (1.3 cm) in size. Rather than exhibiting the traditional warm, red-orange color that is common among most red aquarium fish, these miniature rasboras boast a deep and cool-toned red with distinct black markings.

Scientific Name:Boraras brigittae
Common Name:Chili Rasboras, Mosquito Rasbora
Size:0.5 inches (1.3 cm)
Lifespan:4 to 8 years
pH:4.0 to 7.0
Temperature:68 to 82 F (20 to 28 C)
KH: 3 to 12 dGH
How Many Fish in a 10 Gallon Tank?8

Point Rasboras (Boraras urophthalmoides)

Point Rasboras (Boraras urophthalmoides)

Similar to its cousin the popular Chili Rasboras, this pretty nano fish is colorful, active and can really bring a lot of energy to your 10-gallon community tank.

They usually stay below 0.6 inches (1.6 cm) and school together in a vibrant wave. Like Chili Rasboras, keeping them in groups of at least 6 fish is a must. 

Scientific Name:Boraras urophthalmoides
Common Name:Point Rasboras
Size:0.6 inches (1.6 cm)
Lifespan:4 to 8 years
pH:6.0 to 7.0
Temperature:68 to 82 F (20 to 28 C)
KH: 8 to 12 dGH
How Many Fish in a 10 Gallon Tank?6

Lambchop Rasbora (Trigonostigma espei)

Lambchop Rasbora (Trigonostigma espei)
Photo: wikipedia

the last but not the least Rasbora on our list is the Lambchop Rasbora because they have the distinctive coloration. They sport a brighter orange body and also feature a distinct black mark that resembles a lambchop, starting in the middle of the body and ending on the tail.

Due to their unique marking and peaceful nature, a group of their own kind can nicely pop out against the waving greenery of the real live plants.

Scientific Name:Trigonostigma espei
Common Name:Lambchop Rasbora
Size:1.5 inches (3.8 cm)
Lifespan:4 to 8 years
pH:6.0 to 7.0
Temperature:72 to 79 F (22 to 26 C)
KH: 2 to 10 dGH
How Many Fish in a 10 Gallon Tank?6

Dwarf Gourami (Trichogaster lalius)

Neon Blue Dwarf Gourami

Everyone loves Gourami species because of their ease of care, unique behavior, and stunning appearance. However, not all Gouramis are good candidates for smaller aquariums, some species grow too large for 10-gallon tanks.

Dwarf gouramis are one of the few species that are well suited to 10-gallon community aquariums. They will grow to 2 inches (5 cm), and you can keep them with fish similar size like neon tetras and Rasboras mentioned above. We also like adding a pair of dwarf gouramis to 10-gallon tanks as they will swim together.

Scientific Name:Trichogaster Ialius
Common Name:Dwarf gourami, flame gourami, powder blue gourami, sunset gourami
Origin:India, Bengal, Assam, and Bangladesh
Size:2 inches (5 cm)
Lifespan:4 to 6 years
pH:6.0 to 7.5
Temperature:72 to 82 F (22 to 28 C)
KH: 4 to 10 dGH
How Many Fish in a 10 Gallon Tank?A pair/Single

Honey Gourami (Trichogaster chuna)

Trichogaster chuna

Honey Gouramis are another well-known small member of this family. They are even smaller than Dwarf gouramis and stay around 2 inches (5 cm). Peaceful and undemanding, these fish get along with almost any other species in a 10-gallon fish tank.

As a centerpiece fish, this species stands out with its bright yellow or gold body with two modified ventral fins. Furthermore, Honey Gouramis are more peaceful than Dwarf Gouramis and are less susceptible to Dwarf Gourami Iridovirus (DGIV) disease.

Scientific Name:Trichogaster chuna
Common Name:Honey gourami, honey dwarf gourami, red flame gourami, dwarf fire gourami, red robin gourami
Size:2 inches (5 cm)
Lifespan:4 to 6 years
pH:6.0 to 8
Temperature:74 to 82 F (23 to 28 C)
KH: 4 to 10 dGH
How Many Fish in a 10 Gallon Tank?A pair/Single

Fancy Guppy (Poecilia reticulata)

Photo: corydorablecaliaquariums /instagram

A 10-gallon guppy tank is colorful and lively, which I recommend to aquarists of all experience levels. One reason why guppies have been a staple in the aquarium hobby is they are highly adaptable in many different water conditions.

Fancy guppies are readily available for purchase and come in all sorts of sizes, shapes and colors. Most of them stay small, usually under 2 inches (5 cm). Guppies are great at reproducing, so you don’t need to purchase many of them for a 10-gallon tank. 3-5 fancy guppies should make a good start.

Scientific Name:Poecilia reticulata
Common Name:Guppy
Origin:South America
Size:2 inches (5 cm)
Lifespan:2 to 3 years
pH:6.5 to 8
Temperature:68 to 78 F (20 to 26 C)
KH: 6 to 8 dGH
How Many Fish in a 10 Gallon Tank?3 to 5

Endler’s Livebearers (Poecilia wingei)

Endler’s Livebearers (Poecilia wingei)

Endlers, the little cousins of guppies, surely have their place among the most colorful freshwater fish. Endlers livebearers are smaller than guppies and pretty easy to care for as well.

As with guppies, female Endlers are larger than males because of their rounder abdomen. Usually, males will only grow up to an inch (2.5 cm) in length while females can reach 1.8 inches (4.5 cm). 10-gallon tank should be enough for a small school of 4-6 Endler’s livebearers, although you may need to have 20 or more to get some interesting shoaling behaviors.

Scientific Name:Poecilia wingei
Common Name:Endler’s Livebearers, Endlers
Size:1 inch (2.5 cm)
Lifespan:2 to 3 years
pH:5.5 to 8
Temperature:64 to 82 F (18 to 28 C)
KH: 10 to 30 dGH
How Many Fish in a 10 Gallon Tank?4 – 6

Middle Dwellers

For 10-gallon community tanks, here are many peaceful middle dwellers that remain untroubled to what’s happening in the upper or bottom parts of the water column!

Ember Tetras (Hyphessobrycon amandae)

Ember Tetras (Hyphessobrycon amandae)

For years, Ember Tetras have been a beloved choice for freshwater nano aquariums. Their unique orange hue is bound to catch the eye of countless admirer! At only an inch long, this tiny species will add beauty and life to your tank in no time.

A small 10-gallon aquarium with a lush forest of live aquarium plants would look fantastic against with a school of this flame-colored fish. Because they can be a bit shy and have a diminutive size, it’s best to keep them in a school of at least six fish (of the same species).

Scientific Name:Hyphessobrycon amandae
Common Name:Ember Tetras
Size:1 inch (2.5 cm)
Lifespan:up to 10 years
pH:5.5 to 7.5
Temperature:72 to 82 F (22 to 28 C)
KH: 5 to 17 dGH
How Many Fish in a 10 Gallon Tank?6 – 8

Flame Tetra (Hyphessobrycon flammeus)

Flame Tetra (Hyphessobrycon flammeus)

Another fairly small species of Tetra in the fish trade, the Flame Tetra grow to around 1.6 inches (4 cm) long and do best in schools of at least six. They are very active and often stick together as they swim to and fro.

As its name implies, their back and fins are colored in a brilliant red with black on the leading edge and tip of the anal fin, giving them a very vibrant appearance. At one time, these cute fish were quite popular because they are adaptable enough to handle a wide range of temperatures.

Scientific Name:Hyphessobrycon flammeus
Common Name:Flame tetra, Von Rio tetra, fire tetra, red tetra
Size:1.6 inches (4 cm)
Lifespan:3 to 5 years
pH:5.5 to 7.5
Temperature:72 to 82 F (22 to 28 C)
KH: 3 to 15 dGH
How Many Fish in a 10 Gallon Tank?5

Black Phantom Tetra (Megalamphodus megalopterus)

Black Phantom Tetra (Megalamphodus megalopterus)
Photo: wikipedia

Natives to Brazil and Paraguay, the Black Phantom Tetra is readily available in most fish stores. This species can be distinguished by an “eye patch” marking behind the gills, giving them a phantom-like appearance.

At 1.75 inches (4.4 cm) in length, you could house a group of five or more black phantom tetra in a 10-gallon planted aquarium. They are peaceful, easy to care for and quite hardy, that’s why we find ourselves recommending it over and over again.

Scientific Name:Megalamphodus megalopterus
Common Name:Black phantom petra, phantom tetra
Size:1.75 inches (4.4 cm)
Lifespan:up to 5 years
pH:6 to 7.5
Temperature:72 to 82 F (22 to 28 C)
KH: 3 to 18 dGH
How Many Fish in a 10 Gallon Tank?5

Black Widow Tetra (Gymnocorymbus ternetzi)

Black Widow Tetra (Gymnocorymbus ternetzi)

Also known as the black skirt, this best-known tetra species has distinctive black dorsal and anal fins. In nature, this species actually comes in a range of colors from white to pink, but different varieties with various colors and fin shapes have been developed through selective breeding.

The Black Widow Tetra can reach a size of 2 inches (5.0 cm), these active swimmers would appreciate a 20-gallon tank or larger that is well planted. However, with proper care and in 10-gallon tanks, you can keep a small school of four individuals.

Scientific Name:Gymnocorymbus ternetzi
Common Name:Black tetra, black skirt
Origin:Rio Paraguay, Rio Guapore, Bolivia
Size:2 inches (5.0 cm)
Lifespan:up to 5 years
pH:5.8 to 8.5
Temperature:68 to 79 F (20 to 26 C)
KH: up to 15 dGH
How Many Fish in a 10 Gallon Tank?4

X-Ray Tetra (Pristella maxillaris)

X-Ray Tetra (Pristella maxillaris)

The X-Ray Tetra, or pristella tetra hails from a wide range of habitats from Amazon and Orinoco basins in Brazil to coastal rivers of Venezuela, where it is found in both acidic and alkaline waters. Like Black Widow Tetra and Black Phantom Tetra, its common name comes the see-through body and visible organs as they swim.

It is small, up to around 1.75 inches (4.5 cm) and lives in large groups, preferably of a half-dozen or more. When kept in a 10 gallons fish tank, go for four or more individuals as 6 of them would be a little crowded.

Scientific Name:Pristella maxillaris
Common Name:X-ray fish, X-ray tetra
Origin:Brazil, Guyana, Orinoco, and Venezuela.
Size:1.75 inches (4.5 cm)
Lifespan:3 to 5 years
pH:5.8 to 8.5
Temperature:64 to 82 F (18 to 28 C)
KH: 4 to 8 dGH
How Many Fish in a 10 Gallon Tank?4

Glowlight Tetra (Hemigrammus erythrozonus)

Glowlight Tetra (Hemigrammus erythrozonus)

As one of the fairly new species of tetra introduced to the aquarium trade, the Glowlight Tetra is a highly sought-after commodity. Like the glowlight rasbora, the glowlight tetra is characterized by its iridescent red stripe running horizontally along the length of its slender body.

It’s a peaceful schooling fish that grows to 1.5 inches (3.8 cm) in size, and five would do great in 10-gallon tank. If you want to make a visually stunning 10-Gallon aquascape, we highly recommend putting five of them in a well planted tank with a red centerpiece fish like a pair gourami or red betta fish.

Scientific Name:Hemigrammus erythrozonus
Common Name:Glowlight tetra, glolight, fire neon
Size:1.5 inches (3.8 cm)
Lifespan:3 to 5 years
pH:5.8 to 7.5
Temperature:74 to 82 F (24 to 28 C)
KH: up to 15 dGH
How Many Fish in a 10 Gallon Tank?5

Dwarf or Teacup Platies (Xiphophorus sp.)

Platies like guppies and endlers are Livebearing fish, they give birth to live fry instead of laying eggs. Although most platies grow larger (up to 3 inches or 7.6 cm), with careful selection you can find small “teacup” varieties of platies that are around 1 inch (2.5 cm) in size and perfect for a 10-gallon tank.

In 10-gallon community tanks, a trio of dwarf platies (1 male and 2 females) is a good starting point. Remember most livebearers prefer higher pH and enjoy harder water, so make sure to read up on the water requirements of these fish.

Scientific Name:Xiphophorus sp.
Common Name:Dwarf Platies, Teacup Platies, Teacup Red Wag Platies
Origin:– (Selective Breeding)
Size:1 inch (2.5 cm)
Lifespan:up to 5 years
pH:6.8 to 8.5
Temperature:70 to 82 F (21 to 28 C)
KH: 10 to 28 dGH
How Many Fish in a 10 Gallon Tank?A trio (1 male and 2 females)

Mid to Bottom Level

These species prefer swimming at the bottom and mid levels of the tank:

Neon Tetra (Paracheirodon innesi)

Neon Tetra (Paracheirodon innesi)

Any list of colorful fish would not be complete without the dazzling neon tetra. Despite being small – they usually grow up to around 1.5 inch (3.8 cm) long, neons are a very active shoaling species that prefer living in groups of a half dozen or more.

These small peaceful fish are often mistaken for cardinal tetras. The difference between the two is that cardinals have the bright red stripe running along their entire bodies, while neons have a red stripe that only extends from the middle of the body.

Scientific Name:Paracheirodon innesi
Common Name:Neon tetra, neon fish
Origin:Colombia, Peru, Brazil
Size:1.5 inch (3.8 cm)
Lifespan:5 to 10 years
pH:7 to 7.5
Temperature:68 to 79 F (20 to 26 C)
KH: up to 10 dGH
How Many Fish in a 10 Gallon Tank?6

Otos (Otocinclus Spp.)

Otocinclus arnoldi
Photo: laquariumalamaison/instagram

Commonly known as “dwarf suckers” or “otos”, these small catfish are super cute. Members in this family are recognized by the plates of armor or bony covering body and an underslung suckermouth.

There are 19 described species in this genus with most typically stay below 2 inches (5 cm) in size at adulthood. These fish are also prized for their ability to keep algae in check, they are an excellent addition to 10-gallon tanks as one of the best tank cleaners.

Species Size
Otocinclus arnoldi1.9″ (4.8 cm)
Otocinclus batmani1.5″ (3.8 cm)
Otocinclus bororo1.2″ (3.1 cm)
Otocinclus caxarari1″ (2.5 cm)
Otocinclus cocama1.7″ (4.4 cm)
Otocinclus flexilis2.7″ (6.8 cm)
Otocinclus hasemani1.1″ (2.7 cm)
Otocinclus hoppei1.3″ (3.3 cm)
Otocinclus huaorani1.25″ (3.2 cm)
Otocinclus juruenae0.9 ~ 1.3 inches (2.2 to 3.3 cm)
Otocinclus macrospilus1.4″ (3.5 cm)
Otocinclus mangaba1.3″ (3.3 cm)
Otocinclus mimulus1.7″ (4.4 cm)
Otocinclus mura1.4″ (3.5 cm)
Otocinclus tapirape0.9″ (2.4 cm)
Otocinclus vestitus1.3″ (3.3 cm)
Otocinclus vittatus1.3″ (3.3 cm)
Otocinclus xakriaba1.2″ (3.1 cm)
Data: fishbase

Bottom Dwellers

Bottom-dwelling fish are necessary for any community tank. Not only do they complete the look of your tank, but they also help keep debris from accumulating in the substrate.

For a 10-gallon aquarium, the most commonly kept members are corys and snails. Here are some suitable species.

Panda Cory (Corydoras panda)

Panda Cory (Corydoras panda)

With their docile attitude, Panda Corys can be a great bottom dweller. They have an interesting appearance with black and white patterns that resemble a panda. Like most animals on this list, Panda Corys are social fish and must be kept in schools of their own kind.

Given that they stay below 2 inches (5 cm) and how peaceful they are, a group of 4-5 is perfectly suitable for a 10-gallon community tank.

Scientific Name:Corydoras panda
Common Name:Panda catfish, panda cory, panda corydoras
Size:2 inches (5 cm)
Lifespan:up to 10 years
pH:6 to 7
Temperature:68 to 77 F (20 to 25 C)
KH: 2 to 12 dGH
How Many Fish in a 10 Gallon Tank?4 ~ 5

Pygmy Corydoras (Corydoras pygmaeus)

Pygmy Corydoras would be a good fit for aquarists interested in nano fish. As one of the smallest tropical fish in the hobby, they are usually around one inch long. They prefer to be with more of their kind, you can go up to 6 or so in a 10-gallon aquarium.

A soft sandy substrate is appreciated as they like to burrow. Live plants should be added to the aquarium to keep things natural and help these fish thrive.

Scientific Name:Corydoras pygmaeus
Common Name:Pygmy Corydoras, Pygmy Corys
Size:1 inch (2.5 cm)
Lifespan:up to 3 years
pH:6.5 to 7.5
Temperature:72 to 79 F (22 to 26 C)
KH: 6 to 10 dGH
How Many Fish in a 10 Gallon Tank?6

Salt and Pepper Pygmy Cory Catfish (Corydoras habrosus)

Salt and Pepper Pygmy Cory Catfish (Corydoras habrosus)

This species is not often available in pet shops, but it’s worth checking out online. The Salt and Pepper Pygmy Corys is similar in appearance to a longtime favorite, the Pepper Cory Catfish (Corydoras paleatus) but much smaller, reaching a maximum size of 1.4 inches (3.5 cm).

They are very peaceful and should be kept in groups of at least 6 or more since they are shoaling fish. Soft sandy substrate is recommended for them to burrow if needed.

Scientific Name:Corydoras habrosus
Common Name:Salt and Pepper Pygmy Cory Catfish
Origin:Colombia and Venezuela
Size:1.4 inches (3.5 cm)
Lifespan:up to 3 years
pH:6.2 to 7.2
Temperature:72 to 79 F (22 to 26 C)
KH: 6 to 10 dGH
How Many Fish in a 10 Gallon Tank?6

Snails & Shrimps

mystery snail

Invertebrates like shrimp and snails are great bottom feeders and scavengers. They are not just interesting creatures to watch – they also serve a beneficial role in the aquarium’s ecosystem!

Both of these critters help keep the tank clean by consuming algae, animal debris, and leftover fish food. Therefore, with their assistance your aquarium will never be short on beauty or tidiness.

Which Ones Do You Like Most?

Now that you know some of the 10-gallon community tank fish suggestions, it’s time to choose one! Consider your goals and preferences as you decide which ones to keep and enjoy.

Beyond what water level the fish prefer, size, water conditions, and which other species they are compatible with, must also be considered.

Do your research to make sure everyone in the tank will get along and be happy, because a 10-gallon tank has limited space. With some preparation and thoughtfulness, you can have a beautiful 10-gallon community tank with fish that all get along!

Happy fishkeeping!

9 Best Centerpiece Fish for 10 Gallon Tank (With Pictures)

centerpiece fish for 10 gallon tank

10-gallon fish tanks have a great appeal among first-time aquarium owners because they are small enough to be placed securely on anywhere.

However, contrary to what you might think, small tanks are actually not recommended for new hobbyists since they are far more difficult to manage than medium ones.

If you’ve just invested in a 10 gallons aquarium and you’re looking for a colorful or unusual-looking centerpiece fish that really stands out, take a look at the most popular ones available.

Honey Gourami (Trichogaster chuna)

Honey Gourami (Trichogaster chuna)
Photo: flo.to.fish//Instagram

Gouramis have been in the freshwater aquarium trade for a long time and are one of the most diverse families. Most gouramis are medium-sized tropical fish, but the honey gourami (Trichogaster chuna) is smaller in size and can only grow up to about 2 inches (5 cm) long when fully grown.

These brightly colored fish are native to lakes and rivers in India and Bangladesh. In the wild, they inhabit slow-moving waters with heavily vegetated areas. A fair number of floating plants are appreciated because Gouramis are bubble nest builder that needs floating material for their nests.

This species is often confused with the Sunset Honey Gourami (Trichogaster labiosa), which can grow up to 4 inches (10 cm). Make sure to check the scientific name on the label and select the correct species.

The recommended tank size for a single honey gourami is 10 gallons; a group of three gouramis can live comfortably in a 20-gallon tank.

Scientific Name:Trichogaster chuna
Common Name:Honey Gourami
Origin:India and Bangladesh
Size:2 inches (5 cm)
pH:6.0 – 8.0
Temperature:75 to 82 F (24 to 28 C)
KH: 4 – 15 dKH

Dwarf Gourami (Trichogaster lalius)

Dwarf Gourami (Trichogaster lalius)
Photo: Dr. Nisorgo Omi//Instagram

Like Honey Gouramis, Dwarf Gouramis are very popular and readily available everywhere. These two species of Gouramis are hands down the favorites of the hobby.

Dwarf Gouramis are larger than Honey Gouramis and can reach 3 inches (7.6 cm). They tend to be more aggressive than honeys and have a deeper body shape.

A pair of dwarf gourami is known to swim together at all levels of the aquarium, but the problem is that females are rare in the fish trade because of their dull coloration.

Males have especially brilliant red bodies with stripes and a yellow metallic sheen. Several color morphs of dwarf gourami have been selectively bred, including powder blue, Flame red, or neon blue.

It’s the most common variety found at fish stores, but it may carry a fatal, highly contagious virus called the Dwarf gourami Iridovirus (DGIV). According to recent research, approximately 22% of the commercially available Dwarf Gouramis from East-Asian fish farms are affected by DGIV. [1]. That’s why honey gourami might be a better choice for your 10-gallon tank.

Scientific Name:Trichogaster Ialius
Common Name:powder blue gourami, red gourami, sunset gourami
Origin:India, West Bengal, Assam, and Bangladesh
Size:3 inches (7.6 cm)
pH:6.0 – 7.5
Temperature:72 to 82 F (22 to 28 C)
KH: 4 – 10 dKH

Sparkling Gourami (Trichopsis pumila)

Sparkling Gourami (Trichopsis pumila)

Also known as pygmy gourami or dwarf croaking gourami, sparkling Gourami is less commonly seen for sale in fish stores.

As its name suggests, these small fish show so many vibrant colors and patterns that it looks like they are covered with a metallic sheen or glitter. Unlike most gourami species with a flat, oval-shaped body, this one has a slightly elongated body and a pointed head.

As for size, they typically stay smaller than 1.5 inches (3.5 cm) when fully grown. Therefore, Sparkling gouramis are well suited to small and community aquariums. 

These gouramis are very easy to care for, highly adaptable, and do well with a wide range of water conditions. This fish prefers being in small groups in planted tanks, but in a 10-gallon fish tank, it’s best to keep a pair.

Scientific Name:Trichopsis pumila
Common Name:Sparkling Gourami, pygmy gourami, dwarf croaking gourami
Origin:Laos, Vietnam, Cambodia, and Thailand
Size:1.5 inches (3.5 cm)
pH:6.0 – 7.5
Temperature:72 to 82 F (22 to 28 C)
KH: 4 – 8 dKH

Betta (Betta splendens)

Although bettas and gouramis have the reputation as the two most commonly kept pet fish that are appropriate for small spaces, many people think bettas are a much better centerpiece fish for a 10-gallon tank.

Bettas are brighter in color and have longer fins which make them more visually appealing. Plus, they aren’t as timid and can be more active than gouramis.

However, don’t forget that bettas are much more aggressive due to their territorial nature. If you keep multiple males in one tank, it can lead to aggression. For a 10-gallon aquarium, we suggest keeping just one male betta.

Scientific Name:Betta splendens
Common Name:Betta, siamese fighting fish
Origin:Cambodia, Thailand
Size:3 inches (7.5 cm)
pH:6.8 – 7.4
Temperature:75 to 86 F (24 to 30 C)
KH: 0 – 20 dKH

Scarlet Badis (Dario dario)

Scarlet Badis (Dario dario)

Scarlet badis are aptly named for their bright red coloration. They are one of the smallest known percoid fish species and one of the micropredators, feeding on zooplankton, small crustaceans, worms, and insect larvae in their natural habitat.

Usually, a group of scarlet badis can make a visual contrast against the green of the living plants, creating an eye-catching display as they swim to and fro in the tank.

These fish reach a maximum size of 1.2 inches (3 cm). Given the fact that scarlet badis stay small and can be shy, so choose their tankmates accordingly. 

Males feature more vibrant red than females, whereas females remain dull. As a result, females can be difficult to find but are relished by experienced breeders.

Scientific Name:Dario dario
Common Name:Scarlet dadis, rainbow badis, scarlet gem badis, gem badis
Size:1.2 inches (3 cm)
pH:6.5 – 7.5
Temperature:73 to 79F (23 to 26C) 
KH: 10 – 15 dKH

Peacock Gudgeon (Tateurndina ocellicauda)

Peacock Gudgeon (Tateurndina ocellicauda)

Hailing from the eastern part of Papua New Guinea, these little fish is one of the best beginner fish. They are very attractive, unique, and beautiful, and it’s not hard to see why they are beloved among aquarists. 

Peacock gudgeons are pleasing fish that come in a variety of bright colors. The body consists of a colorful mix of pink, yellow, blue, and black hues arranged in intricate patterns.

Not only do they exhibit some beautiful colors, but taking care of them is a simple task. They’re not fussy and do well in community tanks, as well as a species-only tank where focus is put on the plants. 

Scientific Name:Tateurndina ocellicauda
Common Name:Peacock Gudgeon
Origin:Eastern Papua New Guinea
Size:3.0 inches (7.5 cm)
pH:6.0 – 7.2
Temperature:73 to 79F (23 to 26C) 
KH: 0 – 15 dKH

Gardneri Killifish (Fundulopanchax gardneri)

Fundulopanchax gardneri
Photo: Evan Z//Instagram

Another fairly new and unique fish in the trade, the gardneri killifish has very striking and bright coloring. This fish hails from Nigeria and Cameroon.

These fish are sexually dimorphic. Males can be easily identified by their bright coloration and tinted dorsal, anal, and caudal fins. Females will usually have a duller color and stay smaller than males.

Because this is a somewhat timid fish, it’s best to be maintained in a species-only setup, with two or more females to every male. They also enjoy lots of plants, so a heavily planted tank with softer water would be ideal for these fish. 

Scientific Name:Fundulopanchax gardneri
Common Name:Gardneri Killifish
Size:2.5 inches (6.3 cm)
pH:6.0 – 7.5
Temperature:73 to 79F (23 to 26C) 
KH: 5 – 8 dKH

Shell Dwellers

If you are up for the challenge, shell dwellers from Lake Tanganyika can make a centerpiece for your 10-gallon tank. These fish are beautiful and fun to watch but may require special care to keep them healthy in captivity.

What makes shell-dwelling cichlids unique is that these tiny fighters never stop trying to build their own shells for protection. Tanks should be set up with lots of clean and empty snail shells, as well as a mix of rocks and sand substrate.

They are among the smallest cichlids in the world, reaching a maximum size of 2.5 inches (6 cm). Despite their size, they are aggressive, some species even fierce. To help them flourish in your aquarium, you must recreate their natural environment as best you can.

Neolamprologus brevis2.4 inches (6 cm)
Neolamprologus hecqui3.1 inches (8 cm)
Neolamprologus multifasciatus1.8 inches (4.5 cm)
Lamprologus ocellatus2.3 inches (5.8 cm)

Pea Puffer (Carinotetraodon travancoricus)

While the Pea Puffer, also called Dwarf Puffer, Bumblebee Puffer, and Pygmy Puffer, is possibly the cutest fish on our list. Few people can resist the small size and cute appearance of a pufferfish once they’ve seen one.

However, don’t let the cute little face fool you— they can be feisty and are notorious for nipping the fins of other tankmates, even against their own kind. For this reason, it’s best to keep them in a species-only setup.

Since these critters are carnivorous, you should not keep them with any invertebrates as they will likely attempt to eat them. For a 10-gallon nano tank, you can just keep a single dwarf puffer to ensure a healthy and stress-free environment.

Scientific Name:Carinotetraodon travancoricus
Common Name:Pea Puffer, Dwarf Puffer, Bumblebee Puffer, Malabar Puffer, Pygmy Puffer
Size:1 to 1.5 inches
Tank Level:Mid to Top
pH:7.0 – 8.0
Temperature:72 to 82F (22 to 28C)
KH: 5 – 15 dKH

The Most Common Pitfall: Starting Too Small

Whether you’re establishing your first aquarium or assisting a child with starting an aquarium, the most common mistake is to purchase or accept a tank that is too small. 

With those “plug and play” 10-gallon tanks that are readily available in every pet shop, it may be appealing to go small. However, a small aquarium means small water volume and biofiltration capacity, so a tiny change in key water parameters, like pH, water temp, or ammonia level, can easily become a major problem and leave no room for error.

On the other hand, if you’re limited to tanks under 10 gallons, then you don’t have many stocking options since most centerpiece fish require more room. Bettas and Gouramis are your best bets. 

The most often recommended tank size for beginners is a 20-gallon aquarium, which has sufficient volume, offers plenty of room for centerpiece fish, and gives you more flexibility with stocking.


Time To Hit the Store!

We hope we can add more fish to this list, but the limited size of a 10-gallon tank really restricts us in that regard.

We’d love to know what centerpiece fish you decided on and how it’s doing! Also, if there are any centerpiece fish that you think we should add to the list- let us know in the comments! We’d love to hear your thoughts.

Until next time!

Article Sources:

  1. Detection of dwarf gourami iridovirus (Infectious spleen and kidney necrosis virus) in populations of ornamental fish prior to and after importation into Australia, with the first evidence of infection in domestically farmed Platy (Xiphophorus maculatus) 2015.09.008

Why Is My Betta Fish Turning White or Losing Color?

Betta Fish Losing Color

Bettas attract and fascinate hobbyists of all ages simply because of their jewel-tone colors and long, delicate fins.

However, sometimes unusual can happen, and your betta fish will become to lose their color. The most common change in color is turning white or having dulled coloration.

Today we’re going to talk about the causes of why my betta fish is turning white or losing color and what you can do about it.

Let’s jump in!

How Do Betta fish Get Their Color?

White Bettas

To figure out the reason why your betta is turning white, why don’t we understand why betta fish get their beautiful colors in the first place?

First, let’s start with the fact that the skin of most fish is usually white or even transparent. The actual color we perceive is due to the presence of pigment-bearing cells called chromatophores in the dermis of the fish’s skin.

More than six types of chromatophores [1] that are filled with different pigments have been described in fish, including:

  • Black or brown Melanophores
  • Blue Cyanophores
  • Yellow Xanthophores
  • Red Erythrophores
  • White leucophores
  • Iridescent, metallic Iridophores (or guanophores)

Mature chromatophores are grouped into clusters based on the type of pigments they contain, which lead to various shapes or structures. The colors we see on betta fish are a combination of these groups. 

Studies [2] have shown that the more red erythrophores (containing reddish pigments) betta fish have, the stronger their immune systems will be. Furthermore, the number of Red erythrophores has been linked to reproductive success (RPS) as dark red males are considered more attractive than light red ones to females.

Another interesting fact is that the majority of iridescent or metallic colors on your betta’s skin come from iridophores’ location (layer) within the fish’s skin.

Chromophores are principally determined by genetics, but many factors can play a role in the color of skin in bettas.

Additional factors may include:

Natural source of the pigment: Since fish can’t synthesize their own color pigment, they must absorb them from their diet, which means bettas need to consume amounts of the right type of biochromes (biological pigments) to maintain vibrant colors, especially the melanin and carotenoids. 

Hormones: In response to a change in environment, like temperature, lighting, water quality, or aquarium background, betta fish and other teleosts can directly control the pigment inside their chromatophores through the nervous and hormonal system, resulting in an apparent color change. 

Social Interactions: Similarly, social interactions with other betta fish can also cause rapid changes in colors. This is why they are sometimes called “aggressive colors” because the betta shows its color as a warning sign to potential rivals or predators.

Paint or Dye: You may have heard of or seen “painted fish” or “dyed fish” sold at the local aquarium store. As the name implies, these betta fish are painted or dyed by unscrupulous dealers with synthetic pigments or hormones to make them look unique and attractive.

Unlike biological pigments from living plants or animals that can be absorbed as part of a betta’s diet, the synthetic pigments used to dye or paint fish are injected under their skin and cannot be broken down by their digestive system. As a result, the colors will eventually fade, and your betta fish will resume their natural color.

Why Is My Betta Fish Losing Color or Turning White?


This isn’t a question with an easy answer after reading through the list above. I’ll say in some cases, the loss or changing of colors is more common than you’d think.

Along with many “natural” causes, there are other factors that increase the likelihood of color loss or turning white.

Natural Causes

Let’s face it: At the end of the day, bettas are living creatures and age like any other organism. As they get older, their colors may start to fade or change. When this happens, you won’t need to worry about it too much.


As mentioned above, genetics determine the color of the skin. With a certain genetic background, your betta may turn white or lose its color over time simply due to natural biological processes. You can’t do much about this, unfortunately. Only buying well-maintained fish from a reputable source or breeding your betta fish yourself is a good practice.


It is not uncommon for bettas to change color when they enter breeding mode. As part of this process, males become more colorful for the purpose of attracting female bettas. 

Old Age

Unfortunately, your betta’s colors will start fading when they enter into their twilight years due to the chromatophores becoming less dense. Normally, a betta lives for a maximum of five years. It might start to lose some of its colorings and begin to fade, usually around three years old. 

A Marble Betta

Marble Bettas are known to change colors at times. As long as you have ruled out any of the above causes for the color change, you shouldn’t need to worry. 

Causes Related to the Environment

betta fish tank

Your betta will lose its color from time to time when it lacks essential pigments, inhibits chromatophores development, or is due to a variety of environmental issues.


Just like humans, fish can be negatively impacted by stress. Stress can come from poor water quality, overcrowding, injuries, handling and shipping, and improper water chemistry. Stress for fish is a serious problem that can lead to illnesses, loss of color, and, eventually, death.


The most common cause of color loss in betta fish is a poor diet. Many aquarists are unaware of the importance of monitoring their fish’s betta diet – often feeding expired or low-quality feed with inadequate pigments. 

Ensure you provide your betta with a balanced, varied diet high in protein and color-enhancing nutrients like carotenes, xanthophylls, and chlorophylls.

Type of Substrate and Background

Bettas tend to adjust skin colors to camouflage with the environment. That’s why they may be seen turning white in a pale environment. A better idea would be to have dark gravel and black background in the tank, which will help your betta maintain its vibrant colors.

Need for Privacy

The betta fish may compete for territory when you have a “sorority” or “harem” female community tank. They will need their own hiding place to feel safe and secure. If your betta doesn’t have a suitable hideout, it can cause stress and lead to color loss or fading. 

Temperature & pH Fluctuations

Is your betta fish losing color overnight? This could be due to temperature and pH fluctuations in the water. Ensure your tank is heated to an appropriate temperature and maintains a steady pH level for optimal health. 

Betta Diseases That Can Cause Loss of Color or Turning White

There is a wide range of betta fish diseases that can cause color loss or turning white. Some can be more serious than others. For treatment to be successful, a visit to an aquatic veterinarian is a good idea.


The dulled coloration or discoloration might be the symptoms of protozoa or flukes’ infestations. Most parasites invade the betta fish’s cells when new arrivals are introduced to the aquarium, including fish, snails, shrimps, or decorations.

Here are common parasites that can cause betta fish to become pale or discolored.

Ich (White Spot Disease)

ich in betta fish

Ich, or white spot disease, is the most common protozoal infestation in aquariums and ponds. It’s caused by a large, ciliated protozoan named Ichthyophthirius multifiliis in freshwater fish.

Because of its complex life cycle and rapid reproduction, this disease is highly contagious, and treatment must be provided immediately. This disease may result in a 100% mortality rate when left untreated.

You might be interested to know: What Else Causes White Spots on Fish Other Than Ich? (11 Causes with Pics!)

CausesSymptoms Treatment
Stressed environment
Failure to quarantine your new betta
Using infected equipment or décor
Ich tomonts attached to a fish bag
White spots that resemble grains of salt visible on skin or fins
Clamped fins
Fish scratching against rocks, décor, or gravel 
Missing scales
Fish appearing lethargic
Rapid respiration
Gasping at the water’s surface
Multiple fish died suddenly
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Velvet (Dust Disease)

velvet on betta fish

Velvet, also known as “rust” or “gold dust” disease, is caused by either Piscinoodinium pilularis or Piscinoodinium limneticum in freshwater fish.

This dinoflagellate has a similar lifecycle of ich and attacks the gills and skin of betta fish, causing fine yellowish or pale powder on the skin, hence the names.

CausesSymptoms Treatment
Failure to quarantine
Stressed environment
Using infected equipment or décor
Ich tomonts attached to a fish bag, plants
Gold or rust-colored and velvety film on gills and body
Color loss
Heavy mucous secretion
Gasping at the water’s surface
Clamped fins
Loss of appetite
Labored breathing
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Gyrodactylids in betta fish
Gyrodactylus in Betta fish

Flukes are a group of monogenean trematodes that invade the betta’s skin and gills by using a set of hooks. These microscopic parasites often cause serious damage and can lead to secondary bacterial infections.

Flukes are divided into two groups: Dactylogyrus and Gyrodactylus. The former is often present in the gills, while the latter infects the skin.

CausesSymptoms Treatment
Skipping proper quarantine
Stressed by incompatible species
Poor water quality
Improper diet
Missing scales and red spots on the skin
Loss of color
Excess mucus secretion on gills or body
Scratching against objects by the affected betta fish
Gills moving rapidly
Flashing behavior
Decreased appetite


Costia necatrix

Ichthyobodo necator, previously known as Costia necatrix or simply Costia, is a flagellate protozoal parasite responsible for this disease in freshwater fish.

This parasite feeds on the skin and gills of the fish, producing an excess of mucus in blue or grey colors that gives the fish a steel-grey look.

CausesSymptoms Treatment
Skipping proper quarantine
Poor water quality
Steel-grey look
Excess mucus in blue or grey on gills or body
Rubbing against decorations
Gasping for air
Flashing behavior
Decreased appetite
Copper sulfate,
formalin, or salt


Similar to Costia, Chilodonella is another single-celled, microscopic protozoan. Two species among this genus, C. piscicolaand C. hexasticha, are known to be deadly to freshwater fish.

The clinical presentation of Chilodonella is that your betta fish appears to be covered in a gray, mottled layer on the skin.

CausesSymptoms Treatment
Skipping proper quarantine
Poor water quality
Grey, mottled appearance on the skin
Rubbing the body against decorations
Increased respiration
Loss of appetite
Copper sulfate,
formalin, or salt

Bacterial Infection

From a 10-gallon male betta aquarium to a 30-gallon sorority female bettas tank, no matter your betta aquarium, there are many opportunistic bacteria that live in, on, or around your fish. 

Most of the time, these bacteria are harmless until the immunity system of the betta fish is compromised, and then the bacterial infection will arise.

Like parasite infestations, several bacterial infections cause white, cloudy-looking skin on fish.

Aeromonas spp.

Aeromonas species are recognized to cause a variety of common and troublesome diseases in freshwater aquariums and ponds. All Aeromonas members are gram-negative bacteria. Among them, Aeromonas hydrophila has been considered to be the most harmful to aquatic creatures.

Often Aeromonas infections are found in warm water fish, and they mostly take advantage of fish fry or stressed fish with a compromised immune system. 

Bettas infected with Aeromonas may be easily confused with other diseases and may have many different symptoms. Therefore, a diagnosis based only upon clinical signs is highly unreliable. Visit an aquatic veterinarian is strongly recommended.

Flavobacterium columnare (Columnaris)

Columnaris disease, often referred to as Cotton wool disease, Saddleback Disease, and Cotton Mouth Disease, are named for their classic clinical sign — the white cotton-like spots or patches that develops on the betta’s head, fins, or gills.

This disease is caused by warm water, gram-negative, and strictly aerobic bacterium, Flavobacterium columnare, which is often mistaken for a fungus, given its white or grey mycelial patches.

Fungal Infections (Saprolegnia spp.)

Saprolegnia is a genus of water mold that infects a broad range of fish host species. Some species of Saprolegnia are known as water mold or cotton mold for good reasons – they resemble tufts of cotton.

These fungi are well-known among fish keepers, as they cause white cotton-like lesions on the betta’s body. The infected area will appear to be fuzzy and can spread over the entire body of the betta if not treated right away.

They are often incorrectly treated as Columnaris. So, a proper diagnosis is essential for successful treatment. Saprolegnia is an opportunistic organism, meaning when the root cause (water temperature or quality) has been remedied, and any bacterial infections are treated, it will often self-heal.


Thankfully, your betta fish turning white or losing color does not always mean there is a larger problem. Sometimes it’s just a normal color change.

If you rule out natural causes, then it’s most likely due to a bacterial infection or parasites. You will need to diagnose the underlying issue and treat it accordingly. 

It’s always best to consult with an aquatic veterinarian before you start treatment. The sooner you can identify the problem and treat it correctly, the better chances your betta will have for a quick recovery.

Have you ever experienced this situation with your bettas? Share your experience with us in the comments below. 

Good luck, and take care of your fish!

Article Sources:

  1. How Ornamental Fishes Get Their Color [University of Florida]
  2. Female Mating Preferences As A Result of Coloration And Movement In Betta splendens [Lake Forest College]

Betta Cloudy Eye 101(Symptoms Pictures & Proven Treatment)

Betta Cloudy Eye

Cloudy eye in betta fish is quite common. Luckily, it is easily prevented and treatable with broad spectrum antibiotics and good supportive care.

However, this condition requires immediate attention. When left untreated, your betta fish will lose its eyesight or possibly die.

Like other common eye disorders in fish, the cloudy eye has several potential causes; some are more deadly and contagious than others.

This article deals with the most common causes, symptoms, and treatment options of betta cloudy eye.

What is Betta Fish Cloudy Eye?

why is my bettas eye cloudy

Fish cloudy eye, or corneal opacity, is a condition in which the cornea becomes irritated or inflamed. It may result in an excessive fluid buildup (edema) in one eye or both eyes, causing it to look whitish or slightly opaque

Affected betta fish may exhibit one or more clinical signs of other eye disorders, like popped out, hemorrhages in or around the eye, swelling, and ulcerations.

Several different conditions can contribute to the betta cloudy eye, including ammonia burn, bacterial infection, internal parasites, cataracts, or injury. Correctly diagnosing this disease is important to ensure the best possible treatment.

The Symptoms of Cloudy Eye in Bettas

The most notable symptom of the betta fish’s cloudy eye is the one that has given it its name – an opaque whitish film that covers your betta’s eye. 

Depending on the underlying cause of infections, injury and/or eye malfunction, the betta fish may show other physical symptoms as well.

TraumaFrayed fins
Clamped fin
Missing scales
Damaged eyes
Hiding more than usual
Loss of appetite
Ammonia BurnGasp for breath at the top of the water surface
Purple or red gills
Rapid gill movement
Cloudy eyes
Red streaks on the body and fins
Lethargic and loss of appetite
Laying on the tank bottom
Bacterial InfectionPop-eye
Cloudy eye
Hemorrhages in or around the eye
Milky or shedding slime
Abnormal swimming behavior
Increased respiratory effort
‘Fungus’ on the gill plate, base of the fins occasionally
CataractsIntraoribital condition occurs within the orbit of the eye
The lens becomes opaque (often gray)
The lens doesn’t transmit light efficiently

Internal Parasites

Internal flagellates, especially Spironucleus spp., are most likely to infect young betta fish or fry. Once infested, your betta fish may display the following symptoms:

Disease Symptoms
Hole In The Head Disease Moldy lesions on the head and lateral line (HITH or HLLE)
Cloudy eye
White, stringy feces
Subdued coloration
Loss of appetite
Body and Gill FlukesMissing scales and red spots on the skin
Loss of color
Cloudy eye
Excess mucus secretion on gills or body
Scratching against objects by the affected betta fish
Gills moving rapidly
Flashing behavior
Decreased appetite

Causes of Betta Cloudy Eye

As you see, there are various reasons why a cloudy eye(s) can form, and sometimes the true underlying cause can be hard to determine.

Common causes of betta cloudy eye are ammonia burns, bacterial infections, internal parasites, and injury. Poor water quality is often the root cause of betta cloudy eye.

Often, if only one eye is affected, it is most likely that the betta fish experienced some sort of bacterial eye infection caused by trauma or injury. In bettas, this can be caused by anything from rubbing against abrasive aquarium décor or fighting with another betta.

When both eyes are affected in a well-seasoned or cycled tank, a more serious bacterial infection or parasites are responsible in most cases.

Ammonia poisoning or burns typically happen when setting up a new tank. Elevated unionized ammonia (NH3) level is no joke and will kill your fish fast if not addressed promptly. Further Reading: Betta Ammonia Poisoning: Causes, Symptoms & Treatment


Your betta fish has a better chance of a full recovery if the underlying cause is correctly identified, and the treatment is performed in a timely manner.


Cataracts in fish

Less common in fish, but cataracts can cause betta fish cloudy eye. It’s more commonly seen in older bettas with many factors, including genetics and diet.

Cataracts occur when the lens becomes opaque (often gray) and does not transmit light efficiently, causing vision impairment. There’s no treatment for cataracts in betta fish.

Ammonia Poisoning

ammonia poisoning symptoms

Bettas are among the popular beginner fish; New aquarium keepers may feel eager to add fish, but unfortunately the failure to cycle a new tank properly is a common mistake that can lead to betta ammonia poisoning.

Other Potential Causes Include Combinations Of:

  • Bacteria buildup
  • Chlorinated water
  • The decomposition of organic matter
  • Overpopulation (Fish or/and shrimps, snails)
  • Overfeed


  • Use an ammonia test kit to test the ammonia level in your tank;
  • If it’s above 0.1 ppm, perform a 25% to 50% water change over a few days, and make sure the water added is at the same temperature as the aquarium.
  • Ammonia-lowering chemicals can be added to the tank in severe cases.
  • Increase aeration and filtration with a good filter and air stone.
  • Reducing feeding will help by lowering the amount of waste.

Internal parasites

Parasites that affect the eyes of both freshwater and marine fishes are quite common. There are many different types of parasites, but the cloudy eye in fish is often associated with internal parasites.

Spironucleus spp. (Hexamita)

Hexamita in betta fish

Spironucleus spp. (Hexamita), also known as hole-in-the-head disease, are flagellated protistan parasites that most frequently occur in the intestinal tract of fish [1].

Once infested, your betta fish may produce white stringy poop, and the fish may lose their appetite and become more subdued than normal. Their white, stringy feces can be confused for parasitic flatworms. The lesions are seen on the betta fish’s head or flanks. 

Trematodes (Flukes)

Gyrodactylids in betta fish
Gyrodactylids in betta fish

You may have heard of something called Flukes in fish. They are actually referred to many species of trematodes that only live internally in their host.

Gyrodactylids and ancyrocephalids are the two most common monogeneans in freshwater fish. The former gives birth to live young and is usually found on the skin and eyes, while the latter lays eggs and infects the gills.


Metronidazole has been found to be an effective treatment for internal, single-cell parasites, but it should be given through medicated fish food. If your betta fish is refusing to eat, Metronidazole can also be administered as a bath. 

Seachem Metronidazole 5gram
  • Treats bacterial infections
  • For marine and freshwater use
  • Easy to dose, easy to use. For ornamental fish only.

Author notes: Metronidazole is most effective when combined with Praziquantel in medicated fish food.

Bacterial Infection

As we mentioned in this article, the majority of bacteria that cause disease in betta fish are gram-negative, but contrary to popular belief, most disorders of the eye in fish are gram-positive.

These infections are generally caused by Streptococcus and several other closely related groups, including Lactococcus, Enterococcus, and Vagococcus [2]. Understanding this fact is crucial when choosing the appropriate treatment.


Erythromycin, an effective anti-Gram-positive antibiotic for streptococcus infections, has proven to be quite effective when used in a medicated food mix. Be aware erythromycin can permanently wipe out your tank’s nitrifying bacteria in the biofilter, so having a spare sponge filter to replace during the treatment is very important.

Recommended product: API® E.M. Erythromycin

How to Prevent Cloudy Eye in Betta Fish?

Marble betta

One of the main ways to prevent cloudy eye disorder is maintaining the water quality and ensuring it remains healthy and stable. When the water quality is kept at the proper levels, 0 ppm for nitrite and ammonia, and 20 ppm for nitrates, your betta will be safe from the cloudy eye. To ensure this happens, follow the steps below.

A Regular Water Change

Regularly changing your tank’s water will keep the water quality at healthy levels. For smaller tanks, the water changes need to be larger and more frequent. Whereas, for larger tanks, you will only need to perform a 25% water change each week. 

Clean It Up

Maintain a clean tank. If you have a substrate, you should vacuum it regularly to remove feces and leftover food. Routinely clean the tank’s ornaments, including any silk plants.

Betta Fish Filter

A proper filtration system is a must for betta fish tanks. A betta filter should be able to process the water in your tank with adequate filtration rate and circulation. Change out the filter cartridges as needed.

Do not overstock your tank.

Overstocking betta fish tanks can lead to waste accumulation, eventually leading to poor water quality. 

Tanks smaller than 15 gallons will compromise your betta’s health. They can survive in the smaller tanks but will not remain healthy.

Quarantine All New Additions

Placing new fish or other tank additions, including plants and ornaments, into a separate quarantine tank for two weeks is essential to ensure there are no diseases or parasites the betta can be infected with.

Is Betta Fish Cloudy Eye Contagious?

Depending on the cause of the cloudy eye, betta cloudy eye can be contagious to other bettas. If parasites or bacterial infections cause betta cloudy eye, then it is contagious as long as the life cycle of the parasite or bacteria is not broken.

Is Cloudy Eye Fatal to Bettas?

Any illness that goes untreated in your betta fish can potentially prove to be fatal, although the cloudy eye is least likely to cause death. Your Betta will quickly recover as long as you adjust the water’s quality levels and treat your Betta fish. 

However, if the symptoms worsen or additional symptoms occur, there may not be a cloudy eye, and you will need to start investigating further. You can get a diagnosis if necessary, from your local aquatic center if this is the case. 


With rapid detection and action, cloudy eye betta is easily treated and should not prove fatal. Regular tank maintenance is a must for keeping the water quality at a healthy and safe level. 

Keep in mind that prevention is better than a cure. Be sure to quarantine any new betta or tank additions and regularly test your tank’s water to ensure it remains healthy. 

Good luck!

Article Sources:

  1. Parasitic Diseases of Fish [MerckvVetManual]
  2. Streptococcus, Eye Infections in Fish [Aquarium Pond Answers]

Betta Ammonia Poisoning: Causes, Symptoms & Treatment

Betta Fish Ammonia Poisoning

Ammonia poisoning is a silent and deadly disease that can affect your bettas, and if not caught in time, it can kill them. Typically, ammonia poisoning happens when you are setting up a new (non-established) tank. But it can also occur in established aquariums that have had their nitrogen cycling process interrupted.

Just like humans, excessive ammonia causes serious burns on a betta’s skin, eyes, fins, and gills.

No need to panic! With quick treatment, your betta fish usually recover well from this condition within a week.

Keep reading as we explain the nitrogen cycle, several different causes of betta ammonia poisoning, and the signs you need to look out for to keep your fish healthy and safe in this guide.

The Nitrogen Cycle Explained

The nitrogen cycle

In order to prevent and fight betta ammonia poisoning, you will need to understand more about the nitrogen cycle in an aquarium.

Simply put, the aquarium nitrogen cycle describes how toxic nitrogen compounds like fish waste and other decomposing organic matter in the water get degraded from ammonia to nitrites to nitrates.

The final nitrates are then either converted to free nitrogen gas and removed by way of regular water changes or taken up by aquarium plants and microorganisms (also known as beneficial bacteria).

Unlike the natural nitrogen cycle that occurs in large bodies of water, closed aquariums require their own nitrogen cycle, which must be carefully established and fostered.

What is a Safe Ammonia Level for Betta Fish?

What is a Safe Ammonia Level for Betta Fish

Ideally, the ammonia level in any aquarium should always be 0 ppm. In reality, it isn’t always practical because of the decomposition of biological waste, elevated ph levels, bacterial colonies dying, etc.

So, aside from saying 0 is the ideal number, what is practically safe?

Unfortunately, the answer isn’t crystal clear. While some aquarists say it depends on what test kit you use. 

The readily available API Ammonia Test Kit, for example, shows a safe ammonia range for fish that falls between 0 ppm and 0.25 ppm. Another popular Ammonia Test Kit from Seachem, who has a reputation for being the most knowledgeable manufacturer on the market, has the next level of awareness from 0 to 0.05 ppm.

You may wonder why the Seachem Ammonia Alert requires action at such a lower ammonia level. Although there is no easy answer to this question, one thing is certain: knowing the toxicity of ammonia can help you understand the actual ammonia level in your tank.

What is Ammonia Poisoning (Toxicity) in Fish?

In a typical aquarium, the majority of ammonia is excreted by fish as a byproduct of protein metabolism, mainly through the gills and in small amounts in their urine or across other tissues. It can also be produced naturally from the breakdown of organic matter (OM) and uneaten food.

Ammonia exists in water in two chemical forms: un-ionized ammonia (NH3 or UIA) and ionized ammonia (NH4+). In most tests for ammonia, both forms are measured together, referred to as total ammonia nitrogen (TAN).

Since the ionized NH4+ doesn’t easily cross fish gills and has poor bioavailability, it’s basically harmless to fish or other aquatic organisms, whereas un-ionized NH3 can cross the gill membranes very easily and shift to ionized form (NH4+), causing cellular damage and death. 

So, the “free” or gaseous NH3 is the highly toxic form we worry about. The presence of as low as 0.02 – 0.05 ppm [1] of NH3 can be deadly to fish. 

Effects of pH and Temperature on Ammonia Toxicity
Photo: Virbac

Generally, these two ammonia forms exist at an equilibrium point that is influenced largely by water pH and temperature. As pH or temperature increases, the ratio of NH3 to NH4 + increases, meaning that ammonia becomes more toxic.

Several studies have found that the proportion of NH3 to NH4+ (or ammonia toxicity) is also in relation to the salinity of the water [2]. In some cases, making the water harder can reduce ammonia toxicity. That’s why saltwater fish are slightly more sensitive to ammonia toxicity than freshwater species. 

Back to the above question, you probably already know why the Seachem test kit warns at ammonia levels of 0.05ppm and less because unlike API Ammonia Test Kit tests the total ammonia nitrogen (TAN), it only measures the gaseous, un-ionized ammonia (NH3 or UIA).

Getting Accurate Ammonia Level Test Results

Although the Seachem is the only gas sensor test kit on the market that gives you an accurate reading of free ammonia (NH3 or UIA), it’s not exactly easy to use.

Author notes: It comes with a reagent that allows you to perform a total ammonia nitrogen (TAN) test, but it can be quite tedious and time-consuming.

Personally, I use the API ammonia liquid test kit, as it’s much easier and faster. But to get the most accurate ammonia level readings, I followed a step-by-step guide and Ammonia Toxicity Table developed by the University of Florida [3], which gives me peace of mind when I’ve gotten too busy to test.

Here is a step-by-step guide and an example of calculating un-ionized ammonia with the API ammonia test kit or other test kits that measure total ammonia nitrogen (TAN).

pH 42.0(°F) 46.4 50.0 53.6 57.2 60.8 64.4 68.0 71.6 75.2 78.8 82.4 86.0 89.6
6(°C) 8 10 12 14 16 18 20 22 24 26 28 30 32
7.0 .0013 .0016 .0018 .0022 .0025 .0029 .0034 .0039 .0046 .0052 .0060 .0069 .0080 .0093
7.2 .0021 .0025 .0029 .0034 .0040 .0046 .0054 .0062 .0072 .0083 .0096 .0110 .0126 .0150
7.4 .0034 .0040 .0046 .0054 .0063 .0073 .0085 .0098 .0114 .0131 .0150 .0173 .0198 .0236
7.6 .0053 .0063 .0073 .0086 .0100 .0116 .0134 .0155 .0179 .0206 .0236 .0271 .0310 .0369
7.8 .0084 .0099 .0116 .0135 .0157 .0182 .0211 .0244 .0281 .0322 .0370 .0423 .0482 .0572
8.0 .0133 .0156 .0182 .0212 .0247 .0286 .0330 .0381 .0438 .0502 .0574 .0654 .0743 .0877
8.2 .0210 .0245 .0286 .0332 .0385 .0445 .0514 .0590 .0676 .0772 .0880 .0998 .1129 .1322
8.4 .0328 .0383 .0445 .0517 .0597 .0688 .0790 .0904 .1031 .1171 .1326 .1495 .1678 .1948
8.6 .0510 .0593 .0688 .0795 .0914 .1048 .1197 .1361 .1541 .1737 .1950 .2178 .2422 .2768
8.8 .0785 .0909 .1048 .1204 .1376 .1566 .1773 .1998 .2241 .2500 .2774 .3062 .3362 .3776
9.0 .1190 .1368 .1565 .1782 .2018 .2273 .2546 .2836 .3140 .3456 .3783 .4116 .4453 .4902
9.2 .1763 .2008 .2273 .2558 .2861 .3180 .3512 .3855 .4204 .4557 .4909 .5258 .5599 .6038
9.4 .2533 .2847 .3180 .3526 .3884 .4249 .4618 .4985 .5348 .5702 .6045 .6373 .6685 .7072
9.6 .3496 .3868 .4249 .4633 .5016 .5394 .5762 .6117 .6456 .6777 .7078 .7358 .7617 .7929
9.8 .4600 .5000 .5394 .5778 .6147 .6499 .6831 .7140 .7428 .7692 .7933 .8153 .8351 .8585
10.0 .5745 .6131 .6498 .6844 .7166 .7463 .7735 .7983 .8207 .8408 .8588 .8749 .8892 .9058
10.2 .6815 .7152 .7463 .7746 .8003 .8234 .8441 .8625 .8788 .8933 .9060 .9173 .9271 .9389

Ammonia poisoning testing involves a little bit of science, but the greatest accuracy ensures the ammonia levels will not hurt your betta fish.

Betta Fish Ammonia Poisoning Symptoms

First things first, once your betta fish starts showing behaviors and symptoms of ammonia poisoning, the damaging process has begun already, which should be addressed as soon as possible.

Here is the list of symptoms:

Rapid Gill Movement

The most obvious sign of ammonia poisoning betta is rapid respiration (often near the surface). This effort is evident in the gill movement.

Purple or Red Gills

As mentioned, ammonia is primarily excreted across the gill membranes. Elevated ammonia will damage the very fine gill. As a result, the gills will turn purple or red in color, and they may begin to look inflamed and flared.

Red Streaks on Body and Fins

If the ammonia poisoning is not treated right away, fish start to concentrate ammonia in the blood, causing red streaks on betta’s fins and body.

betta ammonia poisoning vs VHSV

This can be mistaken for the bacterial disease VHSV [4] (short for Viral hemorrhagic septicemia virus), given the similar clinical signs. But they are quite different in color, with red or bleeding on ammonia poisoning betta, while in VHSV the color is more of a rusty brown. 

Lethargic and Loss of Appetite

As the betta’s gills are not functioning properly, it begins to lose its appetite and feel lethargic. Although, loss of appetite can result from various betta diseases.

Laying on the Tank Bottom

As ammonia poisoning progresses, the betta will start to lie on the bottom of the tank and look very weak.

What Causes Betta Ammonia Poisoning

what causes betta ammonia poisoning

Several factors can contribute to ammonia poisoning in your fish tank. Learning about these factors will help you practice preventative maintenance to keep your water conditions healthy.

A New Tank That Hasn’t Cycled Properly

Your fish tank is an ecosystem. When you first set up the aquarium, the ecosystem is rather sensitive. The essential bacteria needed to help break down the ammonia in your tank into less harmful compounds have not yet become fully established.

The tank’s cycling takes approximately 6 to 8 weeks for the bacteria to establish itself. During this cycle, you will most likely see ammonia spikes in the water until the bacteria have become established.

Build Up of Decaying Matter

By doing regular inspections of your tank, you will be able to spot any decaying matter that has the potential to cause ammonia poisoning. Things such as feces, rotten food, dead plants, and biological waste will cause the ammonia levels in your tank to rise, which can result in ammonia poisoning.

If your betta is part of a community tank, then while doing your tank inspection, be sure to look for sick or dead fish. Dead fish will produce high levels of ammonia when they begin to decay.


Excess food will decompose in the tank, leading to ammonia levels rising quickly. It is best to feed your betta fish small amounts of food at a time.

Water Changed Infrequently

Regularly changing the water in your tank will dilute the ammonia buildup by replacing the unclean water with fresh, clean water. Smaller tanks will need to have the water changed out more often than larger tanks. 

To keep your fish healthy, your betta needs a filter in its tank, regardless of popular belief. The filter will help you regulate the ammonia levels.

Bacteria Colonies Die

Every tank should have a healthy bacteria colony. This colony helps to neutralize the ammonia buildup in your tank. However, if your filter stops working properly, that bacteria colony may start dying.

Treating your tank with bacteria-killing medications will also eliminate the good bacteria colony. When the bacteria colony in your tank starts dying off, the ammonia levels will increase, and ammonia poisoning will occur.

How To Treat Betta Ammonia Poisoning

treat ammonia poisoning in betta
Photo: edear10/Reddit

Once a high ammonia concentration has been detected, treatment of ammonia poisoning in betta must be done right away.

Water Changes

Firstly, you should go ahead and perform a 50% water change to lower the pH in the tank. Make sure the new water added is at the same temperature. 

To avoid harming your betta with temperature shock while performing the water change, you should ensure that the new water’s temperature matches that of the water to be replaced.

Ammonia Detoxifier

Adding an ammonia detoxifier to treat your tank is the quickest solution to getting your tank back to normal. It works as a natural ammonia filter that uses an enzyme reaction to convert NH3 to NH4+.

Ammonia detoxifiers reduce the harmful levels of ammonia in your tank rather than getting rid of them altogether. The detoxifiers will reduce the negative effect of the ammonia and bring the levels down to a normal, healthy level, which will benefit the good bacteria in your tank. 

Using an ammonia remover is especially helpful when used with a new tank. We recommend the API brand from Amazon. It’s less than $10 for the bottle and will last you a long time.

How To Prevent Ammonia Poisoning in Betta Fish

betta fish

Preventative maintenance is always better than reactive maintenance. Meaning, you should do whatever you can to prevent ammonia poisoning before it happens rather than needing to treat it after it happens. Here are suggestions for the best preventative maintenance.

Frequent Water Changes: One of the most practical tasks you can perform for your fish tank is frequent water changes. Not only will it help to keep ammonia levels low, but it will also keep the water clean and safe for your fish. 

Add Nitrifying Bacteria: The most important aspect of the nitrogen cycle in an aquarium is nitrifying bacteria. These bacteria help to convert NH3 or NH4+ into nitrite (NO2-) and then into nitrate (NO3-). API has a Quick Start Nitrifying Bacteria that is highly effective and only costs $15.

Add Ammonia Removal Inserts to Your Filter: One thing you can do to help prevent the buildup of harmful levels of ammonia in your tank is to add ammonia removal inserts to your current filter. As the water is filtered, the inserts will remove any traces of ammonia in the water. 

We recommend the AquaClear Ammonia Removal Inserts from Amazon. They are inexpensive, coming in at less than $10 for a three-pack.

Water Filters: Bettas may be a tough breed, but they have basic everyday requirements that need to be met, just like any other fish. Some of those needs are a heater and water filter in their tank. 

Don’t believe the myth that bettas can live in a fishbowl. They need at least a 15-gallon tank with a heater and a water filter. The filter will clean your betta’s tank while removing the ammonia buildup.

Frequent Tank Cleaning: Ammonia can be produced by decaying matter in your fish tanks, such as rotten food, fish waste, or plants. Regular tank cleaning and vacuuming of the substrate should eliminate any remaining debris from your tank.

Adding an Air stone: Air stones will help pump oxygen through your tank by creating flows of tiny bubbles that are then transported all over the tank oxygenating the water, which helps to disperse the ammonia that has begun to build up in your tank.

Air stones are not a necessary addition to your tank, but they are inexpensive to help keep your tank healthy. However, some bettas don’t particularly like them. You will need to test one in your tank to see if your bettas react positively to it. 

Do Not Overfeed Your Betta: Not only will there be leftover food, but the more your betta eats, the more waste it will produce, which adds to the ammonia buildup. 

Only feed your betta enough that they can eat all of it in less than two minutes. Any leftovers should be removed from the tank.

Buy a Reliable Test Kit: Once again, preventative maintenance can save you headaches later, as well as keep your fish healthy and safe. 

An ammonia test kit is a great way to keep track of the level of ammonia in your tank. With regular testing, you’ll know right away if the ammonia levels have begun to rise, and you can act accordingly to reduce the levels safely. 


Preventative maintenance is key in keeping your Bettas safe and healthy. Make sure you are doing your part by maintaining the tank, keeping it clean, and performing regular water testing and changes. 

We hope this article has given you everything you need to keep your bettas safe from ammonia poisoning.

Article Sources:

  1. Aquarium Water Quality: Nitrogen Cycle [Florida Department of Agriculture and Consumer Services]
  2. Literature Review of Effects of Ammonia on Fish [Nature]
  3. Ammonia in Aquatic Systems [University of Florida]
  4. Viral Hemorrhagic Septicemia [Lowa State University]

Anchor Worms in Betta Fish (Will They Kill My Fish?)

anchorworms on betta fish

Anchor worms in betta fish are less common than other parasites like Ich (aka white spot disease) and Velvet. They primarily affect goldfish and koi but can infect any freshwater fish or amphibians, like pet frogs and turtles, that don’t have proper quarantine protocols.

If you spot these macroscopic parasites on your betta fish, action must be taken immediately. The more time that passes without treatment, the harder it will be to remove them.

Keep reading as we talk about what is anchor worm and a few methods of removing them without harming your delicate finned friend.

What is Anchor Worm in Betta Fish?

anchor worm in betta fish

Anchor worms, scientifically known as Lernaea spp., are not actually worms but a group of parasitic copepod crustaceans that primarily infect a wide range of freshwater fish (100+ species), especially wild-caught and pond fish.

Because of its wide global distribution [1], more than a hundred Lernaea and Lernaea-like species have been identified. One of the most recognized Lernaea species, both in the aquarium hobby and in aquaculture, is L. cyprinacea, which is considered as a serious pest around the world.

anchorworm life cycle
Lernaea (anchorworm) life cycle. The entire life cycle may take from 18–25 days at approximately 25°C–30°C.
Credit: UF/IFAS Tropical Aquaculture Laboratory

As its relatives of crustaceans, such as crabs, lobsters, crayfish, krill, and shrimp, Lernaea species have a complex and multi-stage life cycle that can take up to 28 days to complete in tropical water. In code water, it could take up to a year. They don’t need an intermediary host, meaning they are able to swim from one fish to another.

Adult L. cyprinacea mate during the free-swimming stage (around 0.35″ in length [2]). After mating, the male dies, and the fertilized female burrows into the fish’s tissue through the scales, eventually using hook-like appendages to embed itself into the skin and muscle of the fish.

The long and slender “worm-like” growth that extends from the fish’s skin is actually the female’s egg sacs, hence its name.

Can Anchor Worms Kill my Betta Fish?

Anchor worms usually live on the skin, fins, gills, and oral cavity of the betta fish. They will enter the internal tissues after eating away fins and scales.

Although a small number of Lernaea isn’t deadly to betta fish, they might cause irritation to the betta fish, leading to inflammation and hemorrhage, ulceration, damaged fins, and severe secondary bacterial and fungal infections. These secondary infections can increase mortality rates in fish.

When larger numbers of Lernaea are present on the gill, they can interfere with the fish’s breathing, further increasing its mortality.

Symptoms of Anchor Worms in Betta Fish

symptoms of anchor worms in betta fish

In the copepodid stages of Lernaea, they are visible to the naked eye appearing as whitish-green, small, thin threads. The following symptoms and signs are typically seen:

  • Small, thin thread can be seen with the naked eye
  • Fish rubbing or scratching against substrate or tank decor
  • Localized red and skin irritations on the body
  • Ragged and inflamed fins
  • Tiny worms located in wounds
  • Lethargy, lack of movement

Causes of Anchor Worms in Betta Fish

The most common reason for anchor worms is not quarantining new fish before adding them to the aquarium.

The female is quite prolific, producing 250 juveniles (nauplii) every two weeks for up to 16 weeks [3] in warm water above 77° F (25°C).

When you add a new betta fish carrying one or more juveniles or even eggs to an aquarium, they will hatch and spread rapidly. All new additions to your aquarium, including fish, shrimps, snails, and plants, should be quarantined for four to six weeks to ensure they are parasite-free.

We should also mention that anchor worms can also be transferred from fish to fish with netting, filter media, etc., so it’s important to sterilize nets and other equipment after use on infected fish.

Diagnosing Anchor Worms in Betta Fish

Anchor Worms in Betta

You will generally be able to diagnose this condition visually because these external parasites will be attached themselves to your betta fish. 

If you are uncertain, take some clear pictures of the affected area and show them to your local aquatic veterinarian for a more accurate diagnosis under a microscope.

As mentioned, a betta fish with anchor worms will have one or more whitish-green threads measuring 0.4″-0.8″ and hanging from various parts of its body. These can be confused with algae, given their similar appearance. To diagnose this issue correctly, use a magnifying glass and shine a flashlight on the affected area.


Since it can be relatively easy to identify this ailment yourself, the chances of recovery are high. However, varying suggestions are available on how to treat a betta fish that has been infested with anchor worms.

Regardless of which following method you choose; the best practice is to set up a hospital aquarium where you can treat them with chemical medications. More importantly, quarantining fish for more than seven days will break the life cycle of the anchor worm in the tank because larval stages cannot survive without a host for that amount of time.

Using Tweezers

Individual anchor worms can be removed by pulling them out from the fish using a clean pair of tweezers. However, you must carefully pull the entire parasite out, as they sometimes break off and leave the embedded head behind.

Once the anchor worm is out, antibiotics must be used on the infected area to prevent secondary bacterial infections. 

Manual removal is impractical on some sensitive areas such as gills and mouth. In addition, if the parasite has burrowed deeply into tissue, attempting to remove it may cause more trauma than leaving it in. In these cases, other treatments should be sought.

Salt Dip

Aquarium salt (NaCl) – definitely not table salt or Epsom salt, is a cheap, effective, and widely available treatment known to work well against bacteria, fungus, and external parasites. Please keep in mind that MUCH more salt is not safe for plants, snails, and catfish – another reason you should treat anchor worms in a hospital tank.

Also, salt is NOT meant to be a long-term treatment option, but rather it should only be used for the duration of time it takes to cure the infection.

It’s most commonly used in a 30-minute bath, starting with the lowest level (1 tsp per 5 gals) and gradually increasing the concentration if the anchor worms persist.

API AQUARIUM SALT Freshwater Aquarium Salt...
  • Contains one (1) API AQUARIUM SALT Freshwater Aquarium Salt 65-Ounce Box
  • Promotes fish health and disease recovery with increased electrolytes
  • Improves respiration for fish in freshwater aquariums
  • Made from evaporated sea water for all-natural results
  • Use when changing water, when setting up a new freshwater aquarium and when treating fish disease

Chemical Treatments

Because the females are more tolerant of salt, chemical treatments are more effective in breaking the life cycle in some cases. Popular options include:

Potassium permanganate

Potassium permanganate (PP) is a strong oxidizing agent with some anti-parasitic properties. A 30-minute dip in potassium permanganate at a concentration of 2 mg/L will kill larvae or eggs, but adults may survive.

Diflubenzuron or Dimilin

Diflubenzuron, also known as dimilin, is a chiton inhibitor that can kill larvae and molting adults. Usually available in liquid form, Diflubenzuron should be administered at a concentration of 0.066 mg/L.

SOBAKEN Dimilin-X Koi & Goldfish Treatmen 1/2...
  • Dimilin -X Koi & Goldfish Treatment 1/2 gallon Anchor Worm Fish Lice Flukes diflubenzuron

Author notes: Do NOT use household insecticides as they have a special chemical class of active ingredients, pyrethroids, which are toxic to fish.


If you have treated Velvet or ich before, you may have copper medication lying around. Copper sulfate is an alternative anchor worm treatment, but it’s unsafe when your GH is lower than 6, as with many betta tanks.

It’s best to raise the GH to 6 or above by adding Tums tablets and then target anchor worms with the copper sulfate.

When treating anchor worms with a salt or chemical dip, observe the betta fish closely; if there are any signs of distress, immediately remove it from the dip. An air stone should be used to increase the oxygen levels during the dip.

Always put these chemicals away from your pets (and kids!), and wear gloves when handling them.

Afterward, the main aquarium should be sanitized, and all decorations should be disinfected in an effort to remove any remaining eggs or larvae before returning the betta fish back.

How to Prevent Ich Anchor Worms in Betta Fish

Anchor worm is an opportunistic parasite that can make its way into the betta fish tank through water changes, plants, or décor. If you detect the parasite early, you’re more likely to experience a successful outcome. 

The best way to prevent anchor worms is to quarantine any new additions to your aquarium for 30 to 60 days [x].

Closing Thoughts

Fortunately, anchor worm infection is one of the relatively easy betta fish diseases to treat. Although anchor worms are often quite visible, it’s best to get a proper diagnosis before treating the condition using any of the above methods.

Be passionate about quarantining new arrivals, no matter where you get them from.

Good luck, and stay vigilant for anchor worms! A clean tank is a happy tank. 🙂

Article Sources:

  1. Lernaea cyprinacea, Anchor-worm copepod parasite [Marine Invasions Research]
  2. Lernaea cyprinacea [University of Michigan]
  3. Lernaea (Anchorworm) Infestations in Fish [University of Florida]
  4. Anchor Worms [Aquarium Science]
  5. Fish Baths, Dips, Swabs; Including Coral; For Disease, Ammonia, Treatment [Aquarium Answers, Pond]