Apistogramma elizabethae: Characteristics, Care Guide, Breeding

A. elizabethae

Apistogramma elizabethae, or Elizabeth’s Dwarf Cichlid, is a colorful dwarf cichlid that originates from the blackwater habitats of South America. The scientific name was given in honor of Elizabeth Cabot Cary Agassiz (1822-1907), the second wife of J. L. R. Agassiz, who participated in the Thayer Expedition (1865-1866) and was the principal author of a book about the journey. 

There are two main color variations of A. elizabethae available in the trade, including red and blue, depending on the locality from which they were collected. 

There are two main color variations of A. elizabethae available in the trade, including red and blue, depending on the locality from which they were collected. These fish display sexual dimorphism, meaning that there are distinct physical differences between males and females. 

This medium-sized Apistogramma fish also exhibits more aggressive behavior than other Apistos during spawning seasons. 

Their need for very specific water conditions makes them a perfect addition to a Rio Negro biotope aquarium; however, it also makes them challenging to breed.

Before you make the purchase, let’s talk about the characteristics of this amazing fish, how to care for them, and their reproduction requirements.

What is the Native Habitat of Apistogramma elizabethae?

A. elizabethae is native to two main tributaries of the Rio Negro, including the Uaupés River and the Içana River. The Rio Negro is the largest blackwater river in the world, located in northwestern Brazil and eastern Colombia.

The river waters are stained by tannins from decaying organic matter, giving them an almost black tint. This type of environment is also characterized by extremely soft and acidic water, high levels of humic acids, and a low concentration of essential minerals. 

These are the most important water parameters of the native habitat of A. elizabethae.

  • Temperature: 72 to 84° F (22 to 29°C)
  • pH: 4.5 to 6.0
  • General Hardness (GH): < 1 dGH
  • Conductivity: < 10 µS/cm

They often inhabit areas near the river banks where the water is shallow and surrounded by dense forests. The riverbed substrate is composed of fine white sand, a leaf litter layer, fallen branches, and plenty of aquatic vegetation.

Depending on the river where the A. elizabethae was originally collected, their prominent body color will be either red or blue. 

What Are the Color Variations of Apistogramma elizabethae?

The most common color forms of Apistogramma elizabethae are as follows.

  • Apistogramma elizabethae ‘Red’
  • Apistogramma elizabethae ‘Blue’

Apistogramma elizabethae ‘Red’

A. elizabethae ‘Red’ refers to the wild-caught specimens from the Içana River. Males typically have a shiny, metallic blue body with a bright red belly and head. 

Several captive-bred color morphs of this wild form exist. The most common color varieties include A. elizabethae ‘Red Belly’ and A. elizabethae ‘Super Red,’ which may have been color-enhanced with certain foods for more intense red.

Apistogramma elizabethae 'Red'

Apistogramma elizabethae ‘Blue’ 

Apistogramma elizabethae ‘Blue,’ also known as A. elizabethae ‘São Gabriel da Cachoeira,’ is a naturally occurring color form of Apistogramma elizabethae that originates from the town of São Gabriel da Cachoeira, near the Uaupés River. It is rarer than the ‘Red’ counterpart.

In males, the base color of the body is usually silvery blue, accented by bright blue markings on their dorsal fins and yellow bellies. During the spawning season, both males and females exhibit a more intense yellow coloration.

In males, the base color of the body is usually silvery blue, accented by bright blue markings on their dorsal fins and yellow bellies. During the spawning season, both males and females show a more intense yellow coloration. 

However, this variety has not been commercially bred because it is less vibrant than its cousin, the most popular Apistogramma agassizii ‘Blue’.

Apistogramma elizabethae 'Blue'

How to Tell a Male From a Female Apistogramma elizabethae? 

Here are some of the characteristics to tell a male from a female Apistogramma elizabethae.

  • Dorsal fin: The male’s dorsal fin is longer and more pointed than the female’s, and it contains 5-6 spines. The female’s dorsal fin is shorter and even.
  • Pelvic fin: The male’s pelvic fin is elongated and blueish, while the female’s pelvic fin is shorter and mostly black.
  • Caudal (tail) fin: Males develop a lanceolate caudal fin. In females, the caudal fin has vertical rows of small light spots that give the appearance of striping.
  • Coloration: Males are more colorful than females. During courtship and breeding, females will exhibit a yellowish-orange coloration covering the anterior part of their bodies, making their black lateral spots and facial stripes perfectly straight.
  • Size: Males are considerably larger than females.

Keep in mind that juvenile fish smaller than 1.5 inches (4 cm) are too small to tell the differences.

Apistogramma elizabethae male vs female

How Big do Apistogramma elizabethae Get?

Apistogramma elizabethae males can grow to be around 2.5 inches (6.4 cm) in total length, while females tend to be slightly smaller, reaching approximately 1.6 inches (4 cm) in total length.

Are Apistogramma elizabethae Aggressive?

Yes, Apistogramma elizabethae are slightly more aggressive than many other beginner-friendly Apistos due to the males’ harem polygyny mating system. In this system, each male mates with more than two females. A male can be very aggressive towards females who are not ready to spawn.

In the home aquarium, it is generally impractical to recreate this system due to the limited space. As a result, female-female intrasexual aggression occurs quite often, leading to stress and potential injury. 

The females are also extremely protective of their brood, sometimes even attacking the male if he gets too close to the fry. 

To ensure the well-being and longevity of Apistogramma elizabethae, it is best to get either just a trio of one male with two females or a large group consisting of at least three males and 4-6 females.

How Long Do Apistogramma elizabethae Live?

The average lifespan of Apistogramma elizabethae is around two years in captivity, as stated by a 1991 statistical study of 7,532 tank-raised specimens from 23 different Apistogramma species by Dr. Sven O. Kullander. However, it has been reported that they can live up to 5 years under ideal conditions among aquarium hobbyists. 

Small fishes tend to have a shorter lifespan than large ones, and many factors play into how long you can expect your fish to live, including their genetics, diet, water quality, and stress levels.

As with any freshwater aquarium fish, providing good care by creating optimal environments is the key to a long and healthy life for your Apistogramma elizabethae.

How to Take Care of Apistogramma elizabethae in Home Aquariums? 

Here are 10 key tips on how to take care of Apistogramma elizabethae in aquariums.

  • Ensure the tank is big enough. A 20-gallon Long (75 liters) tank is the minimum size for a trio of Apistogramma elizabethae. For large groups, you’ll want to ensure that each female has a brooding territory of at least 12 inches (30 cm).
  • Keep the water in pristine condition. The ideal water chemistry parameters for A. elizabethae include a pH of 4.5 – 6.0, general hardness between 1-3 dGH, conductivity less than 10 µS/cm, and a temperature of 72 – 84°F (22 – 29°C). Perform regular water changes of around 10-15 percent weekly. Conductivity and ph levels must be carefully adhered to for keeping this blackwater species in an aquarium. The very soft, acidic, and low conductivity environments can be created by using a RODI (reverse osmosis de-ionized) water system with peat moss and catappa leaves.
  • Provide ample hiding spaces and visual barriers. Like most other types of Apistogramma, A. elizabethae are cave spawners and like to establish their own territory, so provide them with lots of caves and hardscapes as sheltered areas. Overturned flowerpots and half coconut shells are great options for creating suitable caves.
  • Use a fine sand substrate. A fine-grained sand (0.5-1.7 mm grain size) substrate serves two main purposes: it’s safe for these sand-sifting fish to dig in, and it helps replicate their natural environment.
  • Add live plants. Some floating plants are preferred. Not only do they subdue the lighting, but they also offer aesthetic and biochemical benefits. These floating plants are the best choices for Apisto tanks: Anacharis, Amazon Frogbit, Butterfly Fern, Dwarf Water Lettuce, and Hornwort. 
  • Feed them a variety of live foods. To bring out their classic red and blue coloration and boost their health, offer live foods such as bloodworms, daphnia, baby brine shrimp, and black and white mosquito larvae.
  • Pick compatible tank mates. Ideal tankmates for Apistogramma elizabethae include pencilfish, hatchetfish, South American tetra species, and diminutive catfish like Corydoras catfish and Otocinclus catfish. Some potentially good tankmates may include freshwater angelfish, keyhole cichlid, and Geophagus cichlid.
  • Monitor your fish’s health. Watch your fish for lethargy, loss of appetite, swimming difficulty, loss of color, scratching against decorations, white spots, cloudy eyes, white body film, and any other signs of illness. If you notice any of these symptoms, take action immediately.
  • Quarantine all new additions. Quarantining is a critical step in preventing the spread of parasites and bacterial infections. Make sure to quarantine all new additions for at least 2-3 weeks in a quarantine tank(QT) before introducing them into the tank.
  • Acclimate new Apistogramma fish. You will also need to acclimate your Apistogramma elizabethae either by the drip or float method. Never add a fish directly to the tank water as it will lead to shock and stress.
Apistogramma elizabethae care

How to Breed Apistogramma elizabethae in a Tank?

Here are the step-by-step guidelines to successfully breed Apistogramma elizabethae in a tank.

Step 1: Set up a breeding tank.

Use a 20-gallon long tank as a separate spawning tank with a pH of 5 – 6, general hardness (GH) between 1-3 dGH, and conductivity less than 100 µS/cm (or TDS < 50 ppm), and water temperature range of 75 – 79°F (24 – 26°C).

It’s worth noting pH levels and water temperature influence the sex ratio of fry. Lower temperatures (< 76°F) and higher pH levels (> 5.5) seemed to produce more females, whereas higher temperatures and lower pH levels yielded a higher ratio of males.

The tank should have a fine-grained sand substrate with catappa leaves. Add some floating plants and consider covering the sides of the tank with aquarium backgrounds to reduce light, make them feel more secure, and assist in egg fertilization. A group of pencilfish also sends a strong message to the Apistos that this place is safe for reproduction. These fish are cave spawners, so provide each fish with one or two caves.

Step 2: Get a breeding trio.

The best way to obtain a breeding trio is to purchase a group of at least six juveniles and raise them to maturity together. They will reach sexual maturity around 6 – 9 months of age. When choosing the breeding fish from your own group, look for bright-colored males with the healthiest and most active females.

Alternatively, you can buy a breeding trio of Apistogramma elizabethae online. 

Step 3: Condition them with live food.

After introducing the breeding trio to the tank, feed them live food and monitor them closely to ensure they are getting along well.

Step 4: Watch for the breeding behavior.

In Apistogramma dwarf cichlids, the female starts a courtship ritual to attract the male near her cave. The male will perform tail-beating if he is interested in the female. The courting process may last for several days in new pairs and 2-3 hours in established pairs. 

The spawning takes place secretly in the cave, with up to 30 eggs per spawn being deposited on the ceiling of the cave. In 1 to 3 days, the fry will hatch at 77°F (25°C), and they become free-swimming after three days.

Step 5: Remove the male when required.

The brooding female will viciously protect the fry and might become overly aggressive toward the male. If this happens, it’s best to remove the male.

Step 6: Grow out the fry.

Fry must be fed very small foods, such as infusoria, rotifers, and newly hatched brine shrimp. During this time, ensure the tanks are well aerated and the water is kept very clean. Feed the fry multiple times per day and perform daily water changes.

Apistogramma elizabethae breed

Leaves for Apistogramma: Myth, Top Picks & How to Use

Leaves for Apistos

Are you a passionate aquarium enthusiast looking to breed Apistogramma species? If so, there is one thing you absolutely must get right: the water conditions.

Originating in South America, these delicate dwarf cichlids are found in slow-moving streams and tributaries beneath dense forest canopies, where the water is naturally soft and acidic from the decaying leaves, wood, and other organic matter.

Over the years, the characteristics of their native habitats have led to a common misconception that adding some plant materials like dried tree leaves and driftwood can easily lower aquarium pH and create a Rio Negro biotope aquarium.

But is that really the case? Join us as we explore the truth behind this myth and reveal which leaves are best suited for your Apistogramma tank.

Do Leaves Help Lower pH in an Apistogramma Aquarium?

When you drop some leaves into your Apistogramma aquarium water, they gradually decompose and release tannins, which are plant-based substances that slowly tint the water with a yellow-brown coloration. However, these leaves can only lower the pH in aquariums with low or zero carbonate hardness levels (KH<5).

KH, or Carbonate Hardness, is primarily determined by the concentration of bicarbonate (HCO3-) and carbonate (CO32-) ions in the water. These ions act as buffers, helping neutralize any acids or bases added to the water.

That is to say, if you simply put the foliage in your Apistogramma fish tank with hard, alkaline tap water, the weak tannic acid present won’t affect the pH level other than coloring the water and increasing levels of total dissolved solids (TDS).

Myth: Leaves or Tannins Will Soften Water

Aquarium water hardness (referred to as GH for short) measures the amount of mineral cations in water, with the most abundant being calcium (Ca2+) and magnesium (Mg2+) ions.

While the tannic acid will react with mineral cations, causing them to form complexes and precipitate out of the water, the extent of the softening effect is extremely limited and short-lived in those areas with hard water.

Map of water hardness in the United States

If you live in an area with hard water and want to soften it for your Apistogramma fish, you’ll need to use a reverse osmosis (RO) system to filter the mineral cations. You can also collect rainwater from your roof or directly buy RO water from Walmart, Walgreens, Target, and Whole Foods.

More Benefits of Leaves in Apistogramma Aquariums

Leaves for Apistogramma

On top of helping to lower pH, using leaves in your freshwater aquarium offers numerous advantages for both the tank environment and the well-being of your aquatic pets. Let’s explore some of them:

Promote Humic Substances Formation – Humic substances are large, complex molecules produced by the decay of organic matter (such as leaves). They help to form a strong biological foundation in your tank, binding with trace elements and providing essential minerals for beneficial bacteria and fauna. This is especially important in Apistogramma fry growth.

Provide Natural Shade and Cover – Leaves offer shade and cover for Apistogramma species as they are bottom dwellers.

Alter Tank’s Aesthetics – The brown/yellow tint released by leaves adds a natural, wild-looking feel to your aquarium. Apistogramma species are known for their brightly colored patterns and vibrant colors, and adding some floating plants, driftwood, or leaves helps bring out these unique visual displays.

Act as An Antibacterial Agent – These leaves contain various phenolic compounds, such as flavonoids, coumarins, phenolics, and triterpenoids, which act as natural antibiotics. This helps to protect fish against bacterial and fungal diseases in your tank.

12 Leaves are Best for Apistogramma?

Not all leaves are created equal when it comes to lowering pH in an aquarium—some are far better than others.

We have listed 12 popular leaves below and how they improve your South American biotype or blackwater aquarium environment.

Catappa (Indian Almond) Leaves

Indian Almond leaves

Catapaa leaves, also known as Indian almond or Ketapang leaves, have been widely used for decades in fish farms as an antibacterial and antifungal water treatment.

The size varies from seller to seller, but they usually measure around 4-7 inches (10-18 cm) long and can produce a brown tint in aquarium water. Start with one leaf per 5 gallons of water, and increase it until the desired color is achieved.

Oak Leaves

Oak Leaves for Aquariums

Oak leaves are the most common type used in aquariums due to their availability, tannin content, and ability to lower pH. There are dozens of oak species in North America, and they are divided into two main categories: red oaks and white oaks.

The former makes particularly good choices for aquariums because they decompose slowly, impart a beautiful dark brown/red hue to the water, and have great shape.

Japanese Maple Leaves

Japanese Maple Leaves

Japanese maple leaves are an interesting and attractive addition to your aquarium due to their leaf shape and texture. These leaves tend to break down much quicker than Indian almond leaves.

Hazel Leaves

Hazel Leaves

Hazel leaves are another leaf litter for lowering the pH in your Apistogramma fish tank. The leaves of common hazel (Corylus avellana) are slightly bigger and thicker, but they will last just as long as Catapaa leaves.

However, it does not tint the water deeply and has a milder acidifying effect, which might require more leaves for larger tanks.

Hornbeam Leaves

Hornbeam Leaves

Hornbeam leaves are a popular choice among owners of nano tanks because of their smaller size, typically measuring between 1.5-3.5 inches (4-9 cm) in length. 

They decompose rapidly and can quickly lower the water’s pH, similar to the effect of Catappa leaves. Therefore, you may need to replace them more often.

Sycamore Leaves

Sycamore Leaves

Sycamore leaves have a similar appearance to maple leaves, but they typically have shallower lobes and are arranged alternately on the branch.

Like Hornbeam leaves, Sycamore leaves have a strong and rapid coloring effect when added to aquarium water. However, they decompose quickly and have a short-lived ability to reduce the pH of the water. If not replaced, the pH level will rise again over time.

Magnolia Leaves

Magnolia Leaves

Adding magnolia leaves to your Apistogramma tank offers similar benefits as Catappa leaves because they can produce phenolic antimicrobial compounds to exert antimicrobial effects. 

These leaves come in a variety of colors, ranging from oranges to browns, which makes them an appealing addition to a mixed leaf litter bed in a blackwater aquarium.

Guava Leaves

Guava Leaves

The leaves of the guava tree (Psidium guajava) are rich in antibacterial properties and can boost the overall health of your Apistogramma aquarium. 

They are popular with dwarf cichlid hobbyists who like to add dried leaves that dissolve much more slowly. In addition, their coloring makes them especially attractive for recreating a natural habitat for Apistos.

Mangrove Leaves

Natural Mangrove leaves have been used by Apistogramma keepers for years to maintain a stable, acidic environment.

They are small in size, durable, and last longer, so they can be used to add depth to your aquarium. They don’t strongly tint the water, but they do impart an amber-brown hue.

Jackfruit Leaves

These tropical botanicals provide a good alternative for conditioning aquatic habitats and are known for their aesthetics, abundance of antibacterial properties, and phytonutrients. 

As you can see, they have a very solid shape that brings a nice effect to your aquarium with a beautiful golden-brown color.

Mulberry Leaves

Like jackfruit leaves, mulberry leaves are a highly beneficial leaf litter to Apistogramma aquariums. Not only do they provide an aesthetically pleasing Nature style habitat, but they also serve as a natural food source for shrimp and snails.

Banana Leaves

Did you know that banana leaves possess the highest concentration of tannins among agricultural wastes and are considered a potent source for manufacturing leather in tanning processing and wood adhesive?

In the freshwater aquarium, aquarists often use dried banana leaves to add a natural look and flavor to their tank. As they decompose, they slowly release tannins and other beneficial substances into the water that can help soften it and reduce pH levels.

How to Use Leaves in Apistogramma Tanks?

To prepare these leaves for your aquarium, first, rinse them under running water to remove any dirt or debris. Then, you can either let them air-dry or brew them over with some boiling water to make them sink immediately. 

Don’t boil or pre-soak them for too long. Otherwise, they will lose their natural tannins and color quickly, and you don’t get their benefits.

When adding the leaves to your aquarium, simply place them on the water’s surface, and they will slowly sink to the bottom after a week, or you can weigh them down with a decoration.


Do Beech Leaves Lower the pH in An Aquarium?

Beech leaves are low in tannins and will only slightly reduce the pH.

How Many Leaves Should I Put in My Aquarium?

It depends on your tank size, tap water parameters, the type of leaves you are using, and the desired water conditions, like pH and TDS.

As a general rule of thumb, start with a few leaves and monitor your water parameters for any changes. Adjust the number of leaves accordingly to reach your desired results.

Can I Collect Leaves from Outside for My Apistogramma Aquarium?

Yes, you can do so, but only if you are certain they have not been exposed to any chemicals or pollutants, such as fertilizers and pesticides. Damaged or rotten leaves should also be avoided.

Last Words

While adding leaves to your aquarium can help lower its pH, it is important to note that this method does not act as a miraculous fix. Adjusting pH should be a gradual process to prevent stressing your Apistogramma fish. 

Next time you are thinking of using leaves effectively to lower the pH, get an RO/DI unit or buy RO water to supplement your water changes.

Speaking of Apistogramma tank set-up, check out our comprehensive section to help you create a suitable environment for these beautiful dwarf cichlids.

How To Acclimate New Apistogramma Fish? (Drip or Float Method)

Apistogramma Acclimation

Welcome to the fascinating world of Apistogramma fish! These stunning dwarf cichlids are renowned for their vibrant colors and fascinating behaviors, making them a highly sought-after addition to any dwarf cichlid enthusiast’s collection.

But before you can witness their beauty in full bloom, it’s crucial to properly acclimate them to their new environment. Don’t let the stress of relocation harm your new aquatic friends.

Read on to learn the proper Apistogramma acclimation method that guarantees a smooth transition and promotes optimal health.

The Importance of Proper Acclimation for New Apistogramma

Upon receiving your Apistogramma fish from an online source or store, proper acclimation is essential, especially for wild-caught specimens since they are more sensitive to environmental changes.

By acclimating your newly-received fish, you can help them adjust to the water parameters in their new home as quickly and stress-free as possible, reducing the risk of acclimation shock – one of the biggest killers of new aquatic animals.

Apistogramma Acclimation Methods

Although the goal of a slow and careful acclimatization process is the same, the methods and nuances behind it have evolved over the years as new knowledge becomes available.

When it comes to acclimating Apistogramma and other aquatic life, the two most commonly used methods are the floating bag method and drip acclimation.

Floating Bag Method

Aptly named, this 1960s method is straightforward:

  1. Simply place the sealed shipping bag in your quarantine tank (QT) and let it float to equalize the temperature. This gradual process usually takes 15-30 minutes, depending on the temperature difference.
  2. Once the equalization period is over, open the bag and take 1/2 cup of water from the QT and add it to the bag.
  3. Repeat it every 15-20 minutes until the shipping bag is full.
  4. Take the bag out of the QT and pour about half of the water from the bag down the sink.
  5. After that, float the bag in the QT and repeat step 2.
  6. Net the fish from the bag, discard the water into a sink and carefully add the fish into the QT.

Reasons Why the Floating Bag Method Is Not Ideal for Apistogramma Acclimation

While there are several variations based on this broad approach, in most cases, it is a poor way to acclimate Apistogramma species unless you can buy them from local breeders (or LFS) within a driving distance of less than an hour.

Here is what you need to know about the defects of the floating bag method; they are quite clear and reasonable.

If you purchase Apistogramma online and not at a store, it may take a day or two for the fish to be delivered to your doorstep. During transit, the water temperature in the shipping bag can drop a bit, resulting in a reduction in the fish’s metabolic activity.

ammonia poisoning

However, despite this, the accumulation of carbon dioxide and ammonia from the fish’s waste can still increase the acidity of the water in the bag. As you probably already know, ammonia exists mainly in the form of ionized ammonium (NH4+) at low pH and temperature, which is relatively non-toxic.

When you get the shipping bag float in a tank with warmer water, where the fish’s metabolism is ramped up and produces more carbon dioxide (CO2) and ammonia waste.

Once the bag gets opened, the carbon dioxide is released, and the excessively increased pH level converts the ammonia to the un-ionized form (NH3), which is a hundred times more toxic and can burn your Apistogramma’s gills.

On top of causing ammonia burns or even sudden death in fish, consider the following potential problems associated with the floating bag method.

  1. Hailing from soft, acidic water, Apistos can be very vulnerable to pH and temperature changes.
  2. It is possible that parasites or other disease-causing organisms can enter your tank by hitchhiking at the bottom of the shipping bag from the pet store.
  3. The increase in the fish’s metabolism means oxygen depletion in the fish bag. This lack of oxygen may cause your fish to suffer from hypoxia.
  4. Most often, the outside of the bag’s inner lining is dirty, even has debris inside, and should not be floated.
  5. Some breathable bags can allow the gas exchange through the bag’s wall, which creates a relatively stable environment. Once the fish bag is immersed in the aquarium, however, this process can be disrupted.
  6. Keeping any fish in a polluted, confined space longer than necessary is a poor husbandry practice.

Introduce the Squirt & Dump Method for Tank-raised Apistogramma 

Now that you understand why the floating bag method isn’t ideal for Apistogramma let’s talk about the squirt & dump method.

The concept behind this technique is to add a few drops of water conditioner into the transport bag to neutralize the ammonia once the temperatures have equalized. Popular water conditioners like Novaqua plus or Seachem Prime can make the water safe for your new fish arrivals by detoxifying the excess ammonia.

Once you have made the most important parts of the game of conditioning the water, your next step is determined by whether your Apistogramma fish is tank-raised or wild-caught.

For commonly tank-raised Apistogramma specimens like A. agassizii “Fire Red” or cockatoo dwarf cichlid, which can handle a wide range of pH and temperature conditions than their wild-caught counterparts, you can go from step 2 of the floating bag method if you want.

While many aquarists prefer to transfer the fish into the quarantine tank (QT) right away rather than leaving them in a bag where ammonia levels are increasing, as they believe this is less stressful for the fish.

Acclimating Wild-caught Apistogramma with the “Squirt & Drip Acclimation”

For those wild-caught Apistos, you may have to use the drip method. This technique has been widely accepted at the hobby level for decades as the “advanced” way of acclimating sensitive aquatic life to a new environment.

What is Drip Acclimation?

The “drip acclimation” or “bucket method” is considered the gold standard among hobbyists of all levels. It works by introducing quarantine tank (QT) water to a bucket at a precise rate of drips per second using a handmade siphon device.

Initially, the Drip Acclimation Method was advocated mostly by saltwater marine aquarium hobbyists who have to monitor a wider scope of water parameters to acclimate new arrivals, not just the water temperature. 

However, the same principle applies to sensitive Apistogramma fish because the difference in pH levels and Total Dissolved Solids (TDS) between the transport bag water and the QT water can easily shock the fish.

As a general rule, if the TDS (Total Dissolved Solids) or pH are different by more than 50mg/L or 1.5 pH points, respectively, there’s no doubt that you should use the Drip Acclimation Method for your newly-purchased fish.

Instructions for the Drip Acclimation Method

Before starting the acclimation process, gather the following items:

  • A clean bucket or a specimen container (thanks to their small size, a 2.5- or 5-gallon bucket work sufficiently for Apistogramma fish)
  • A length of aquarium airline tubing and an airline control valve (not necessary)

Once you have all the materials ready, here’s how to do it:

  1. Float the bag: Start by floating the sealed bag containing the fish in your aquarium. This will equalize the temperature inside the bag with your QT water, reducing temperature-related stress.
  2. Open the bag and neutralize ammonia: After 15-20 minutes, open the bag and quickly add a dose of a water conditioner like Novaqua Plus or Seachem Prime. This step neutralizes the ammonia in the bag, preventing additional stress and potential ammonia burns to the fish.
  3. Transfer fish to the bucket: Place the Apistogramma fish, still in its transport bag, inside the bucket or container. Carefully open the bag and pour the water, along with the fish, into the bucket.
  4. Start siphoning: Gently coil the aquarium tubing around the rim of the bucket, secure it in place with a clip, and create a siphon between the aquarium and the bucket. Attach the control valve or tie a loose knot in the airline to control the water flow.
  5. Adjust the drip rate: Aim for a slow drip rate of about 1-2 drops per second, and this can be achieved by adjusting the control valve or making the knot tighter. Don’t let the drip rate become too slow, which can cause the water to cool too quickly.
  6. Pour out half the water once the water doubles. Regularly monitor the water level in the container. Once it has doubled, remove half of the water and repeat the dripping process five times until the water from the shipping bag in the container to less than 10%.
  7. Net the fish to the quarantine tank (QT): Once the acclimation process is complete, gently use a net to transfer your new Apistogramma fish to your QT, making sure to avoid transferring any of the water from the bag.

Tips for Preventing Problems with Your Apistogramma Fish During Acclimation

To make the acclimation process go as smoothly as possible and reduce the chances of problems arising, keep these tips in mind:

  • Make sure there is enough place in the bucket.
  • Test the pH and water temperature when the water is doubled.
  • You might want to pull the knot tight if it’s a really sensitive fish.
  • When acclimating both fish and invertebrates, it is recommended to use a separate bucket for each.
  • It can be helpful to turn off the lights of your aquarium during the acclimation process to avoid shocking your Apistos.


The floating bag acclimation is more suitable for hardy dither fish, such as tetras, pencilfish, or rasboras.

But if you’re a first-time Apistogramma keeper, the Drip Acclimation Method is recommended as it will help to reduce stress and provide better protection for your delicate fish.

Hopefully, this guide will help you feel more confident in choosing the right acclimation process for your Apistogramma fish. If you are unsure or have any questions, don’t hesitate to reach out for help. 

How Many Apistogramma Should Be Kept Together?

how many apistogramma in 20 gallon

One of the most common questions asked by new Apistogramma owners is, “How many Apistogramma can be kept in a 20-gallon or 55-gallon aquarium?” It’s a logical question, as most fish keepers who become interested in having these diminutive fish tend to have small- to medium-sized tanks.

But, it’s also a tough question to answer. Depending on the size of your aquarium, the species of Apistogramma you have, and what type of aquarium you are going to set up, you may have come across hundreds of opinions about how many fish can be safely housed together.

Luckily, as with anything, there is a very rough Rule of Thumb. Read on to learn the general recommendations and factors that will most impact your Apistogramma stocking levels.

Rule of Thumb

How Many Apistogramma Can I Put in a Fish Tank?

If you’ve had any exposure to the fish-keeping world, you may have heard the most widely-known rule for stocking a tank: one inch of fish per 1-2 gallons of water. While this rule applies well to other small community fish (3 inches or less), it does not apply to dwarf cichlids due to their aggressive and territorial nature.

Instead, an accepted “Rule of Thumb” in the Apistogramma hobby is that each fish should have a territory of approximately 12 inches (30 cm) in diameter. 

This is a good starting point, but there are several factors to consider when stocking an Apistogramma tank before one can be sure that the fish will have enough space and territory in the bottom area.

How Many Apistogramma Can I Put in a Fish Tank?

Given their small size, this simple rule makes it much easier to calculate how many Apistogramma you can stock in your aquarium.

As you may guess, a wider tank is more suitable for keeping Apistogramma as it provides a larger footprint, allowing the fish to establish their own territory.

The chart below lists the most common aquarium sizes, their dimensions, a’s well as the number of Apistogramma that the aquarium can safely house within the recommended territory.

Tank SizeDimensions (L x W x H)Number of Fish
10-gallon (Breeding)20″ x 10″ x 12″A pair/trio
15-gallon24″ x 12″ x 12″A pair
20-gallon (long)30″ x 12″ x 12″A pair
29-gallon 30″ x 12″ x 18″A pair
30-gallon (breeder)36″ x 18″ x 12″A pair/trio
40-gallon (long)48″ x 12″ x 16″A harem of one male with 3 females
55-gallon48″ x 13″ x 21″A harem of one male with 3 females
75 gallon48″ x 18″ x 21″A harem of one male with 3 females
125-gallon72″ x 18″ x 21″A harem of 2 males with 4 – 5 females

Factors Affecting the Number of Apistogramma in a Tank

Once you get to the point where you want to stock more Apistogramma than the chart above would suggest, there are several factors that will come into play. 

Aquarium Type

The two basic types of fish tanks in the Apistogramma world are community-type tanks and breeding tanks. Remember a community tank can never be used as a breeding tank.

A 10-gallon aquarium is the most commonly available tank and is both inexpensive and large enough to breed almost any Apistogramma species, whether it’s a breeder pair or a trio of one male and two females. Never keep more than one male in a 10-gallon spawning tank.

The stocking density in a community tank is a bit more complicated since various species of Apistogramma cichlids will have different temperaments, breeding practices, sizes, aggression levels, and living conditions.

Breeding Practices & Aggression Levels

When selecting an Apistogramma species for your community tank, choose carefully. Some species, such as Agassiz’s dwarf cichlid (A. agassizii), Three-Striped Apisto (A. trifasciata), and Banded Dwarf Cichlid (A. bitaeniata), are strictly polygamous and tend to be quite demanding and aggressive. Other species, like A. borellii and A. steindachneri, practice opportunistic polygamy, where the male will attempt to breed with any female as the opportunity arises, without any exclusivity.

When stocking these polygamous species, it is recommended to keep a harem of one male with at least two females. This ratio helps to ensure a more peaceful environment for the fish and reduces the male’s aggression, especially when a female is not ready to spawn.

Ensure each female has her own hiding spot and the room to establish and defend her territory. The less aggressive the species are, the more fish you can have.

Tank Mates & Preferred Tank Levels

apistogramma tank mate

An attractive community tank of Apistogramma can be created by incorporating other peaceful and small fish species that prefer different water levels rather than competing for the same space. As a bonus, it gives you more room to raise more Apistos in the tank.

Since Apistos are known as bottom dwellers that stay primarily on the bottom of the tank, fishes that prefer the middle and top levels of the aquarium are ideal tank mates.

Good choices are Neon Tetras, Pencilfish, hatchet fish, and other small dither fish. Make sure to select tankmates that can tolerate similar water parameters as Apistogramma cichlids; otherwise, they may not do well in such an environment.


Next, think about aquascaping. When starting out in aquascape design, the goal should be to create a natural landscape that closely mimics Apistogramma’s native habitat, rather than designing something that is merely aesthetically pleasing to you.

The design principles for aquascaping a tank used for Apistogramma should be based on providing lots of hiding spots and boundaries. A great way to do this is by adding necessary elements, such as live plants, driftwood, dead leaves, rocks, and caves, that provide the illusion of different levels in the tank.

Simplicity is your friend. Many aquarists tend to overdo it by adding too much in the tank, which can make it look cluttered and as well as make a difference in the amount of fish that can successfully be kept.

Keep in mind that some plants thrive in different conditions, and floating species are always appreciated by Apistogramma. 

Last Words

Apistogramma are cichlids with very strict stocking densities. When stocking, stick to the general rule of providing them with abundant territory instead of the “One Inch per Gallon” rule of thumb.

Always research the species of Apistogramma that you are interested in prior to purchase, and never buy fish on impulse. Carefully select tank mates for your Apistos so that they have enough room to live and can co-exist peacefully.

Finally, don’t forget about aquascaping! Set up an attractive habitat with plenty of hiding spots and features that re-create their natural environment. This will give your Apistogramma cichlids a better chance for long-term success in the aquarium.

Goldfish Cloudy Eye (s): Causes, Symptoms & Treatments [with Pictures]

goldfish cloudy eye

Cloudy eye(s) in goldfish is not a disease but a condition caused by a wide variety of possible underlying problems. Unfortunately, goldfish can’t tell us what’s wrong, so it’s up to us goldfish parents to figure out the cause and find an appropriate treatment. 

This condition can be a serious symptom of bacterial infection and parasites – particularly when the cloudiness is on both eyes. Of course, when a single eye is infected or damaged, it can still indicate something is wrong.

Don’t panic! In our experience, many goldfish can successfully recover from a cloudy eye by following the proper treatment plan. 

What is Cloudy Eye(s) in Goldfish?

Usually, a cloudy eye involves the cornea (the transparent outer covering of the pupil) of the goldfish becoming inflamed or accumulating excessive tissue fluid behind one or both eyes [1], giving it a cloudy, opaque, or swollen appearance. 

In some cases, depending on the goldfish varieties and severity of the illness, the fish may show other physical symptoms and behavioral changes, such as bulging eyes, clamped fins, lethargy, buoyancy problems, etc. 

Fancy Goldfish with Protruding Eyes

Bubble Eye Goldfish has protruding eyes

Fancy goldfish refers to different varieties of goldfish (Carassius Auratus) that have been specifically bred to develop certain physical characteristics. 

Some have enhanced body colors or shapes, some come in flowy double tails, and some are known for their naturally protruding eyeballs. Of course, this is definitely not the Popeye disorder.

While goldfish varieties with protruding eyes, like telescope-eye goldfish (Red Moor Goldfish) and Bubble Eye Goldfish, can be a beautiful sight to behold, they are also more susceptible to developing cloudy eyes due to their large, delicate eyes are prone to cuts, and tears from tank decorations and tank mates.

What Causes Goldfish Cloudy Eye?

Based on years of experience, the cloudy eye goldfish can be due to physical trauma, bacterial infection, parasites, and water quality issues. 

Like Popeye, the cloudy eye disorder in goldfish may be unilateral (a single eye) or bilateral (both eyes).

When only one eye appears cloudy, it’s more likely associated with trauma rather than an infection and poor water quality. Luckily, in this case, the cloudy eye will eventually go away as it heals.

If both eyes are affected, some infections and/or water quality issues may be blamed. It’s critical to identify the underlying cause and take appropriate action, or it will cause the fish to die. 

Water Quality Issues

Poor water quality is one of the most common causes of goldfish illness and death. Goldfish are messy eaters and poopers. This means goldfish tanks can become very dirty rather quickly if not maintained properly. 

Among these important water parameters, ammonia levels and water temperature are mainly responsible for the cloudy eye in goldfish.

Ammonia Poisoning

Ammonia Poisoning in goldfish

As you may already know, ammonia poisoning usually occurs when you first set up a goldfish tank, but it can also happen in a “mature” aquarium due to the poor functioning of the nitrogen cycle, where ammonia formed from fish waste and uneaten food is converted by beneficial bacteria into nitrite, then nitrate, and finally back to air.

When ammonia gets too high due to overfeeding or overpopulation, your fish’s eyes may appear cloudy; however, this is less noticeable than the following signs.

Red or purple gills
Bloody patches or streaks on the body
Ragged or frayed fins
Laying at the bottom of the tank
Difficulty breathing
Loss of appetite
Uncycled aquarium
Chemically treated tap water
Increased fish byproducts
Overstocking & Overfeeding
Incorrect pH levels


It’s important to note that ammonia poisoning can be fatal to goldfish, so prompt action is critical. The first step is to test the ammonia level with a standard test kit. If the reading rises above 1 ppm, start treatment immediately by following these steps:

  1. Reduce ammonia levels: Perform a partial water change (50% or more) to dilute the toxic ammonia levels in the aquarium.
  2. Improve water quality: Add a high-quality aquarium water conditioner to remove chlorine, chloramines, and heavy metals from tap water.
  3. Add bacteria: Add a bacteria supplement to the aquarium to establish a healthy biological filter.
  4. Increase aeration: Increase the aeration in the aquarium by adding an air stone or increasing the power of the existing air pump.

Gas Bubble Disease (GBD)

Gas Bubble Disease in goldfish

Gas Bubble Disease (GBD) in goldfish is a condition that results from gas supersaturation [2], leading to symptoms such as small bubbles trapped within a fish’s eye or tissues. 


In GBD, the most obvious sign is the presence of small bubbles behind or inside the eye, though they may also be found in other parts of the body, such as fin rays and operculum (gill openings).


  • Cracked or loosely connected pipe or filtration component.
  • Sudden changes in water temperature.
  • A sudden rise in pressure.
  • Abundant algae growth in ponds


To treat GBD, it is essential to determine the source of the excess gases. Check the pipes, filters, and water temperature. Never try to burst the bubbles, as this will often bring secondary bacterial infection.

Physical injury

As mentioned, some varieties with protruding eyes are vulnerable to abrasion that can cause localized inflammation. As a result, you may notice your goldfish’s eye turn cloudy or exophthalmic (popped out), depending on the level of the injury.

There is no treatment for traumatic eye injuries in fish. Preventative measures such as providing a safe environment with smooth surfaces, clean water, and silk aquarium plants are essentialial.

Bacterial Infection

Goldfish frequently develop cloudy eyes as a result of bacterial infections. If both eyes are cloudy and swollen, it’s likely that bacterial infections are present.

Virtually the root causes of bacterial infections are related to poor water conditions in the aquarium.

Streptococcus spp.

Although most aquarium bacterial infestations are Gram-negative, fish eye disorders are usually caused by Gram-positive bacteria, specifically Streptococcus species or related bacteria, including Lactococcus, Enterococcus, and Vagococcus [3]. 

Streptococcal (often shortened to Strep) outbreaks can cause high mortality rates (> 50%) over a period of 3 to 7 days. Unlike most common opportunistic fish bacteria, such as Aeromonas or Columnaris, Strep can be more aggressive and even fatal.


The noticeable sign of Strep disease is usually cloudy eyes (corneal opacity-whitish eyes). You may see a variety of other signs of illness as well.

  • Enlarged eyes (exophthalmos)
  • Hemorrhages in the eye, gills, or the base of the anal fin
  • Excess mucus
  • Difficulty swimming
  • Lethargy
  • Darkened coloration


For moderate Strep infections, a hospital tank with API® E.M. Erythromycin (Erythromycin Phosphate) will work. In severe cases, Seachem NeoPlex used in a medicated food mix is recommended. 

Aeromonas spp.

Goldfish and koi are the most popular cold-water fishes, which are susceptible to Viral Hemorrhagic Septicemia (VHS), a highly infectious and lethal virus caused by the Aeromonas species.

Aeromonas is a group of Gram-negative, facultative anaerobic bacteria, with A. salmonoid (commonly called Furunculosis) and A. hydrophila being among the best-known species. Both species are causative agents to be linked to causing hemorrhagic streaks or ulcers in the fins, tail, gills, and skin.


Hemorrhages may also be seen in the internal muscle and organ tissues. In some instances, goldfish may exhibit other signs such as exophthalmia (pop-eye), cloudy eyes, ascites (distended abdomen), discoloration, abnormal swimming behavior, and loss of appetite.


Given the fact that Aeromonas are Gram-negative, facultative anaerobic bacteria, treatment is currently limited to antibiotics. However, treating them in cold water (below 65°F) can be challenging as many antibiotics lose efficacy.

Seachem KanaPlex (Kanamycin), a Gram-negative antibiotic, mixed with fish food, has proved to be effective in treating Aeromonas infection.


Many types of protozoan parasites can also contribute to cloudy eyes in goldfish. They enter your fish pond or aquarium are the result of failure to quarantine new fish, plants, or other decorations.

The most common of these are:

Epistylis spp.

Epistylis in goldfish

Several Epistylis species (ciliated freshwater protozoan) are known to infect the skin, fins, and gills, resulting in irregular white spots on the fish’s eyes and other body parts. Epistylis in cold water fish is not common but may break out during the warmer months.


Epistylis infestation is often confused with ich due to similar white spots on the skin. However, it can be differentiated by the irregular shape and translucent coloration of the spots.


Maracyn 2 or Kanaplex medicated fish food can be effective. However, to kill the Epistylis on the fish’s eggs, the tank should be treated with Malachite green.

Eye Flukes (Diplostomum spathacaeum)

The eye fluke (Diplostomum spathacaeum) [4] is a microscopic parasite that can infect warm-water and cold-water fishes. Occasionally, tiny worms can be seen wriggling around in the goldfish’s eyes. These parasites can be tough to eradicate, as they often invade the fish’s eye lenses, where they are protected from the host’s immune system.


The infected goldfish often have enlarged and cloudy eyes.

As the parasite replicates and spreads, the goldfish will generally become blind in the infected eye, affecting its feeding and growth.


Unfortunately, there is no effective treatment currently available to treat eye flukes. 


Another serious but uncommon eye disorder that goldfish can suffer from is cataracts. This condition occurs when the lens of the eye becomes cloudy or opaque, reducing the vision of the fish. This can be caused by various factors, including genetics, injury, infection, or old age. There is also no known treatment or cure for goldfish cataracts.

In conclusion

Goldfish cloudy eye(s) can be caused by several factors and should always be addressed as soon as possible. Treatment options include antibiotics, parasite medications, and supportive care.

Unfortunately, cataracts and eye flukes are untreatable and may cause permanent vision loss.

For a successful treatment, always consult your aquatic veterinarian for the best recommendations. They can provide personalized advice for goldfish care and treatment when needed.

Good luck!

Article Sources:

  1. Aitchtuoh, Fischer. Treating Pop-Eye. Central Florida Aquarium Society
  2. Effects of Total Dissolved Gas Supersaturation in Fish of Different Sizes and Species. National Library of Medicine
  3. Streptococcal Infections of Fish. University of Florida
  4. Diplostomum spathacaeum. Wikivet

Hammerhead Catfish Care Guide: the Rare and Expensive Cats

Hammerhead Catfish

Sometimes known as Bottlenose catfish or dolphin catfish, the Hammerhead Catfish, as you might expect from such a descriptive and fascinating name, have a head that is large and flat and is shaped, unsurprisingly, like a hammer. 

There are a few different species from the genus Ageneiosus that go by this common name, with A. marmoratus being the most widely available. It is also worth noting that A. marmoratus has been recently considered a junior synonym of A. inermis.[1]

These unusual catfishes were only recently revised but have been in the hobby for some time as they are interesting and attractive fish.

Without further ado, let’s find out a bit more about these peaceful and good-looking cats.

Species Summary

Bottlenose catfish (Ageneiosus marmoratus)
Photo: shadowshador

Ageneiosus is a small group of driftwood catfish (or wood cats) found mostly throughout South America. It includes 13 scientifically described species, only of two of which are available in the aquarium hobby: A marmoratus (Jaguar Dolphin Cat) and A. magoi (Orinoco Dolphin Cat); the latter is not seen in the trade very often.

Thanks to their small full-grown size, they can make a suitable addition to many freshwater community tanks. However, they are somewhat less popular catfish because of their high price tag.

Driftwood catfishes are nocturnal, meaning they will be active and come out to feed during the night and hide in logs and caves during the day.

The species of the Auchenipteridae family have a unique evolutionary reproduction process that involves internal fertilization. Males develop a modified anal fin that serves as a copulatory organ, allowing for the fertilization of eggs inside the female. This process is similar to that of livebearers, such as guppies and mollies.

Colors and Markings

Hammerhead catfish or dolphin catfish (Ageneiosus spp.) are aptly named for their hammer-shaped heads, wide mouths with lips, and elongated bodies.

The bodies of hammerhead catfish are typically dull in coloration, as seen in the Jaguar Dolphin Cat (A. marmoratus), with black blotches of various sizes serving as camouflage in their natural habitat. On the other hand, the Orinoco Dolphin Cat (A. magoi) boasts a yellowish hue and distinctive broken stripes, making it a visually appealing species in an aquarium setting. Unfortunately, these black marble markings mostly fade as the fish matures

Many other members of the Ageneiosus genus are also commercially valuable and often prized by experienced fish keepers. Identifying young individuals can be challenging, as their distinctive features may not yet be fully developed. If you are lucky enough to come across one of these species and are looking for traits to verify its identity, here is what you should look for:

Ventral view of pectoral of Ageneiosus intrusus
Ventral view of pectoral of Ageneiosus intrusus (Photo: TFS)
SpeciesStandard length (SL)
A. akamaiAnal fin: (31 -) 34 (- 37) soft rays
Caudal fin: 17 soft rays | deeply forked | top and bottom approximately the same length
Dorsal fin: I / 6 rays
Pectoral fins: (11 -) 12 (- 13) soft rays
Pelvic fins: 6 soft rays
A. apiakaAnal fin: (40 -) 42 soft rays
Caudal fin: 17 soft rays | deeply forked | little longer at the top than at the bottom
Dorsal fin: I / 6 rays
Pectoral fins: 12 (- 14) soft rays
Pelvic fins: 6 soft rays
A. dentatusAnal fin: (40 -) 44 (- 49) soft rays
Caudal fin: 17 soft rays | deeply forked | little longer at the top than at the bottom
Dorsal fin: I / 6 rays
Pectoral fins: (11 -) 13 (- 15) soft rays
Pelvic fins: 6 soft rays
A. intrususAnal fin: (37 -) 46 soft rays
Caudal fin: 17 soft rays | deeply forked| having a dark band on the outer edge
Dorsal fin: I / 6 rays
Pectoral fins: 13 (- 16) soft rays
Pelvic fins: 6 soft rays
A. lineatusAnal fin: (32 -) 34 – 35 (- 38) soft rays
Caudal fin: 17 soft rays | deeply forked| having prominent dark stripes
Dorsal fin: I / 6 rays
Pectoral fins: (12 -) 13 (- 15) soft rays
Pelvic fins: 6 soft rays
A. magoiAdipose fin: present
Anal fin: iv – v / 29 – 35 rays
Caudal fin: 8 + 9 soft rays | straight to convex
Dorsal fin: I / 6 rays
Pectoral fins: (11 -) 12 (- 13) soft rays
Pelvic fins: 6 soft rays
A. militarisAdipose fin: present
Anal fin: iv – v / 29 – 35 rays
Caudal fin: 8 + 9 soft rays | deeply forked, symmetric | straight, pointed
Dorsal fin: I / 6 rays
Pectoral fins: (12 -) 13 (- 14) soft rays
Pelvic fins: 6 soft rays
A. pardalisAnal fin: (35 -) 38 – 39 (- 43) soft rays
Dorsal fin: I / 6 rays
Pectoral fins: 13 soft rays
Pelvic fins: 6 soft rays
A. polystictusAdipose fin: present
Anal fin: iv – vi / (26 -) 31 – 32 (- 33) rays
Caudal fin: 17 + 8 (- 9) soft rays forked / concave, round
Dorsal fin: I / 6 rays | straight
Pectoral fins: 13 – 15 soft rays
Pelvic fins: 7 soft rays
A. ucayalensisAdipose fin: present
Anal fin: v – vi / 34 – 42 rays
Caudal fin: 8 + 9 soft rays | deeply forked / concave, pointed
Dorsal fin: I / 6 rays
Pectoral fins: (12 -) 14 (- 15) soft rays
Pelvic fins: 6 soft rays
A. uranophthalmusAdipose fin: present (may rudimentary)
Anal fin: IV – V / (37 -) 43 (- 45) rays
Caudal fin: 17 soft rays | deeply forked | concave, pointed | little longer at the bottom than at the top
Dorsal fin: I / 5 rays
Pectoral fins: 12 – 13 soft rays
Pelvic fins: 6 soft rays
A. vittatusAdipose fin: present
Anal fin: iv – v / (30 -) 32 – 35 rays
Caudal fin: 8 + 9 soft rays | slightly forked | concave, pointed
Dorsal fin: I / 6 rays
Pectoral fins: 12 (- 13) soft rays
Pelvic fins: 6 soft rays
Sources: Journal of Fish Biology | suedamerikafans


Hammerhead catfish can be kept in an aquarium and survive in captivity for 10 years, around 15 years in some cases. This is much longer than their predicted survival in the wild which would be shortened due to being prey to larger fish and changing climates.

Hammerhead Catfish Size

Selecting the right species is crucial when it comes to keeping a catfish. Some start small but can reach impressive sizes; the common pleco (Hypostomus plecostomus) is a good case in point. 

Hammerhead catfishes, luckily, are of relatively small size, making them ideal for aquariums. But a few are capable of growing to an enormous length of almost two feet and are better suited for outdoor ponds.

SpeciesStandard length (SL)
Ageneiosus akamai6.9 inches (17.4 cm)
Ageneiosus apiaka8.0 inches (20.3 cm)
Ageneiosus dentatus9.8 inches (24.8 cm)
Ageneiosus intrusus11.0 inches (28.0 cm)
Ageneiosus lineatus6.3 inches (16.0 cm)
Ageneiosus magoi6.8 inches (17.2 cm)
Ageneiosus militaris11.8 inches (30.0 cm)
Ageneiosus pardalis16.9 inches (43 cm)
Ageneiosus polystictus16.9 inches (43 cm)
Ageneiosus ucayalensis12.2 inches (31cm)
Ageneiosus uranophthalmus9.1 inches (23 cm)
Ageneiosus vittatus8.1 inches (21.3 cm)
Ageneiosus marmoratus7.3 inches (18.5 cm)
Sources: Fishbase | Journal of Fish Biology

Habitat and Care

Hammerhead cats are very hardy and easy to keep. The most important part of their care is providing a suitable, quiet, daytime resting place since these nocturnal bottom dwellers are somewhat loners and shy, preferring their own company in a dimly lit or darkened area.

Since most Ageneiosus specimens sold now are wild-caught, causing them more prone to be stressed from improper water parameters, and may be picky with commercial dry food, so be patient and persistent.

Hammerhead Catfish Tank Size & Growth Rate

Ageneiosus magoi

It depends on which species you are keeping. Keep in mind a fully grown A. inermis can reach 23 inches (59 cm) in length. So, be sure to verify the species before making any decisions.

Ageneiosus are slow to moderate growers; I’d say they have a steady growth rate. The last A. marmoratus I got was about 2 inches from a local dealer, and I got it to 9 inches in 6 months.

Water Parameters

Ageneiosus can be found in diverse habitats ranging from white water to black water. The water temperature is not a crucial factor, however, it’s recommended to have moderately soft water with a slightly acidic to neutral pH.

Try to mimic the conditions from their natural habits to give your hammerhead a better chance of thriving.

As they are predatory species, these cats require a well-oxygenated environment, so it’s important to consider the tank size and filtration system. Make sure to use an efficient aquarium filter that can provide a high water turnover rate.

Like any other catfish, they are susceptible to poor water conditions. A weekly 30-50% water change is recommended to prevent the occurrence of diseases. 


Naturally, their favorite levels are at the bottom, frequenting woody and sandy areas. A soft sandy substrate is preferred though it is not essential. However, hiding spots created by plenty of driftwood, roots, plants, and caves are a must, especially with other nocturnal species or bottom feeders. 

Care should be taken not to overcrowd the tank with such items as lots of room is required for swimming and exploring its habitat. They are good swimming cats and cruise around a lot!

Not only does driftwood make suitable shelter, but it also acts as a substrate on which they can feed on biofilm and algae.

Similarly, dried oak leaves are a good choice for Hammerhead cat care as they provide hiding spots, release tannins to lower the pH level, aid the development of fish fry by promoting the tank’s fauna growth, and add a nice natural touch to the tank.

Due to their nocturnal behavior, dim lighting is necessary. To observe their nighttime activities, a moonlight lighting fixture can be used.

Diet and Feeding

Speaking of diet, larger Ageneiosus differ from other members of the catfish in that small fishes and invertebrates make up most of their natural diet.

As obligate carnivores, it’s crucial to offer a variety of live foods for hammerhead catfishes, including feeder guppies and goldfish, beef heart, shrimp, and chicken. This will ensure that they receive the proper nutrition they need.

Newly acquired aquarium fish can be weaned off of a prepared diet consisting of frozen aquarium food, such as whitebait, brine shrimp, or shellfish. Some individuals will adapt to carnivore fish food, but it takes time.

In the past, I had problems finding live food. I never found my marmoratus to be interested in pellets (Hikari sinking carnivore pellets) or even earthworms and daphnia. The only thing that worked was feeder fish.

On a side note, feeder fish may carry diseases or parasites. It’s crucial to quarantine them before introducing them to your aquarium to avoid any potential health risks to your fish or other aquatic inhabitants.

Bear in mind that these species are active at night, so it’s best to feed them in the aquarium during the night when the lights are turned off.

Behavior and Tank Mates

Hammerhead catfish are fairly peaceful cats, but only when they are not in mating season – during mating season is the time in which they may become naturally more aggressive. 

They may be territorial, so care must be taken to house only with calm tank buddies of a similar temperament and size. Any smaller fish that can fit in their large mouths may be seen as potential prey and should not be kept in the same tank.

As far as tank mates go, I’d suggest keeping them with other small South American cichlids.


Attempting to breed the Hammerhead Catfish in an aquarium can be difficult, bordering upon almost impossible, but with the right equipment and environment, it can be done.

Males Vs. Females

Ageneiosus species do not have any distinct external features until they are ready to breed.

During the breeding season, males tend to have large, rigid dorsal spines and develop a long barbel that can extend past their anterior eye when pressed against the side of their head.

After the breeding season, these two sex characteristics become less pronounced, making it nearly impossible to differentiate between the sexes.


Unfortunately, no reliable sources indicate that Ageneiosus species have been successfully bred in home aquariums; however, reproduction is presumably similar to that of other family members.

Closing Thoughts

Hammerhead catfish are more uncommon and expensive fish in the aquarium hobby, so finding them in a store may be a challenge. Sometimes, they may pop up in fish-keeping communities, but usually, you’d have to order them from online shops.

If you are lucky enough to get one, these cats provide a nice addition to the aquarium with their unique shapes and breeding behaviors as long as you have a realistic understanding of their requirements. 

If you happen to have any questions about one of these cats, particularly A. marmoratus, let me know!

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]