Lemon Oscar (Astronotus ocellatus) Care Guide & Species Profile

Lemon Oscar (Astronotus ocellatus)

Are you an oscar cichlids fan and want to make a stunning addition to your aquarium? If so, then look no further than lemon oscar. This freshwater fish is an appealing color variety of the Oscar Cichlid, making them a worthy choice for your community aquarium. 

Like any variety of Oscar fish, these vibrant lemon yellow Oscars are not quite belligerent and aggressive, but they can swallow any fish that fits into their mouths due to their hearty appetite. Despite their natural aggression, these are easygoing fish, making them an ideal collection for beginners and pro aquarists alike. 

Still thinking about whether adding Lemon Oscar is the right decision or not? Here’s a comprehensive guide covering everything about this striking oscar cichlid variety, including ideal tank mates, suitable food, and tank parameters. Scroll down the page and decide accordingly. 

Species Summary

The Lemon Oscar is a selectively bred color variety of the extremely popular Oscar cichlid in the aquarium community. Though wild-caught Oscars are still readily available, there are many color morphs of this freshwater fish that have been developed over the years.

While their ancestors used to originate from the region of Amazon Basil in South America, these species are now accidentally found in the natural environments of Australia, China, and Florida as a resulting offshoot of the aquarium trade.

Lemon Oscars belong to the genus Astronotus, scientifically known as Astronotus ocellatus. Aquarists know them by their common name, Lemon Oscar or Lemon Yellow oscar. 

There are only two species in this genus, A. crassipinnis and A. ocellatus. Both species are found in the Southern Amazon basin, while the lesser-known A. crassipinnis can also be found in the Paraná–Paraguay basins.

Scientific Name:Astronotus ocellatus
Common Name:Lemon Oscar, Lemon Yellow Oscar
Origin:South American
Aggressiveness:Large Aggressive – Predatory
Max Size:10 – 12 inches (25 – 30 cm)
Lifespan:10 to 13 years
pH:6 – 8
Temperature:72 to 86° F (22 to 30° C) – Aim for 80 – 86 ° F
KH: 5 – 19 KH
Tank Size:Minimum: 75 Gallons | Optimal: 125 Gallons


Lemon Oscar (Astronotus ocellatus)

What makes the lemon oscar a desirable pet for most fishkeepers is its eye-catching coloration and unique appearance. As its name suggests, they feature an opaque, creamy-white body with vibrant lemon yellow coloring, and their coloration and appearance make them visually different from other dark-colored Tiger Oscars. 

Their eyes are pretty large, and the yellow coloration is mostly present on their sides and is rarely patterned. These fish are long and egg-shaped with symmetrical and standard caudal fins. Owing to the unique shape of dorsal and anal fins, these species look like big torpedoes swimming in aquariums. 

Lemon Oscar Size

The average Lemon Oscar size is around 10 – 12 inches (25 – 30 cm) when fully grown.

Oscars are one of the fastest-growing fish in the hobby you’ll come across. The average purchase size of Lemon Oscar is between an inch and 2 inches. You can expect a growth rate of up to one inch (2.5 cm) a month for the first seven or eight months of their life, slowing thereafter. Most of the time, Lemon Oscars can easily grow up to 7 – 8 inches inside a year.

As always, there will be differences between individuals. Some Lemon Oscars will grow a little faster than others, while some may not reach their full potential size if the environment or diet isn’t ideal.


Just like other popular captive-bred varieties, the average lifespan of Lemon Oscar typically ranges between 10 and 13 years with optimal care. However, they can survive for 15 years as well with excellent care and a well-balanced diet. 

If you fail to care for these fish properly, their lifespan will be significantly reduced. So, it would help if you kept that in mind before adding Lemon Oscars to your home aquarium.

Additionally, being a well-known selectively-bred variety, genetics can influence the lifespan of Lemon Oscar cichlids. If they are bred by parents with a long lifespan, you can expect the same from their offspring. Therefore, purchasing from reputable breeders is another important factor in getting Lemon Oscars that can live long in captivity.

Lemon Oscar (Astronotus ocellatus) care

In the wild, Oscars are native to shallow, slow-flowing streams and waters rivers with muddy or sandy bottoms. They will thrive in the aquarium that replicates their natural habitat. 

While these fish are hardy, easygoing, and long-lived, it doesn’t mean that you can skip over their care. They are still cichlids, after all, are will require some effort to manage their temperament in captivity.

Here’re a few Lemon Oscar care guidelines to follow. Get the basics right and make these fish happy and healthy for a long time. 

Tank Size

A minimum of 75 gallons (48″ x 18″ x 21″) with a sump or heavily filtered tank is required to keep an adult Lemon Oscar. 

Some aquarists suggest that you can go for 55 gallons (48″ x 13″ x 21″). It’s acceptable but not recommended as it’s too narrow for the fish to be able to turn around.

According to my first-hand experience, for a single Texas Cichlid, I recommend a tank size no smaller than 125 gallons (72″ x 18″ x 21″). If you are planning to breed them in captivity, make sure to keep a pair in a tank as large as 150 gallons (72″ x 18″ x 28″).

Always ensure that you have an appropriately-sized tank before adding these species to give them enough space to grow. 

Water Parameters

Once you have chosen the right tank size, it’s time to set the ideal water conditions to keep the Oscars. These are freshwater species that do fine as long as the water is clean and clear. 

Remember that water conditions are directly related to their growth rate and lifespan; thus, shouldn’t be compromised. Stick to the ideal tank conditions and avoid changing the water chemistry too often. 

Lemon Oscars are VERY messy eaters and will produce a large amount of waste. Therefore, you must be dedicated to doing a 50% water change every week.

In terms of filtration, I recommend using a sump because of more water volume. If you don’t have a sump, then use two “rated” canister filters. Lemon Oscars are messy fish and will require high filtration rates. The Fluval FX4 is a high-performance canister filter that will work perfectly for a Lemon Oscar tank.

Fluval FX4 High Performance Canister Aquarium...
  • Enhanced Performance: Multi-stage filter pumps out 700 US Gal (2,650 L) of water per hour, with the...
  • Self-Starting: Just add water, plug in and Smart Pump technology will take over. Any trapped air is...
  • Multi-functional Utility Valve: Drain at the base makes it possible to empty the canister and perform...
  • 4-Stage Filtration: Four removable filter baskets eliminate water bypass and hold up to 1 US Gal (3.9 L)...
  • Compact and Quiet Design: FX4 canister filter stands 16.5” (42 cm) tall and easily fits under most...

Follow the parameters mentioned below to avoid any trouble later on.

  • pH: 6.0 – 8.0
  • Water Temperature: 72 to 86° F (22 to 30° C) – Aim for 80 – 86 ° F
  • Hardness: 5 – 19 KH
  • Ammonia: 0 ppm
  • Nitrite: 0 ppm
  • Nitrate:<30 ppm

Decor (Plants and Substrate)

Oscars prefer living on a deep sandy bottom; Adding fine sand or small gravel to their aquarium as a substrate is suggested. Moreover, place a few large rocks and driftwood to offer them visual barriers. 

Keep in mind that these cichlids love digging up plants. Using floating plants is a good idea. Anacharis, hornwort, and water sprite are some of the best floating plants that Lemon Oscars love.

Having said that, these fish will not bother live plants if they are potted in gravel or rocks. Java Ferns and Amazon Swords are some of the best aquarium plants that you can go for.


Lemon Oscars are carnivores with a large appetite. In the wild, their diet consists of smaller fish, crustaceans, insects, and worms. These fish are opportunistic feeders, which means that they will eat anything they can into their mouths.

In captivity, you can feed them live, frozen, or pellets food. Goldfish, feeder guppies, and worms are some of the best live foods that Lemon Oscars love as they grow larger. You can also offer them frozen foods like bloodworms, daphnia, and brine shrimp.

Meats from warm-blooded animals should be avoided as they can lead to dangerous intestinal blockages.

They also accept vegetables and fruits like peas, carrots, and zucchini. Frozen peas have been proved to be a secret weapon to boost the Lemon Oscar’s coloration and vigor.

Oscar cichlids will also accept pellets as a staple diet. I recommend using high-quality pellets that are rich in proteins and nutrients. Some of the best pellets for Lemon Oscars are Hikari Cichlid Gold, New Life Spectrum, and NorthFin Foods. The NLS is the best pellets that I have used for Oscars, but it’s somewhat costly.

New Life Spectrum Cichlid Formula 1mm Sinking...
  • New Life Spectrum is made from quality natural ingredients
  • Extreme Color enhancement and vitality in your fish
  • Made in the USA

Lemon Oscar Tank Mates

Lemon Oscar Tank Mates

Although Lemon Oscars are not as territorial as other cichlids, they are predatory and can consume anything that can easily fit into their mouth. Owing to this, you should choose the appropriate tank mates.

These species are mild-mannered and are best kept either in a species-only tank or with other identical-sized fish that can hold their own.

If you want to keep your Lemon Oscars in a mixed cichlid community. Firstly, the tank size should be at least 200 gallons or more. Secondly, Lemon Oscars should be the last fish to add to the aquarium as they are quite aggressive. Also, slow-growing fish like convict cichlid and Firemouths might be bullied by Lemon Oscars. It’s a high risk to introduce these fish with Lemon Oscars at the same time.

Avoid keeping small fish like Neon Tetras, Guppies, and Platies as they will end up becoming Lemon Oscar’s snacks.

Some good Lemon Oscar fish tank mates include:

The list is not exhaustive, and there are many other Lemon Oscar-friendly fish that you can introduce in the aquarium. It all depends on your fish’s temperament and tank size.


Lemon Oscars are easy to breed in captivity. They become sexually mature when they reach about 4.5 inches (11.4 cm). They are egg layers and open water spawners. Using flat smooth stones to create spawning flats is recommended.

To induce Lemon Oscar spawning, you should increase the water temperature between 78.8 – 86° F (26 – 30° C). The pair will clean a suitable spawning site together before the female Lemon Oscar lays eggs.

The female Lemon Oscar will lay about 1000-2000 eggs. They are excellent parents and will take care of the brood together. The fry will hatch after 2-3 days, and the parents will move them to a pit or cave. Free swimming fry should be fed on Cyclops. 

Final Thoughts

So, that’s all about Lemon Oscar care fundamentals. We hope this post has helped you learn more about these beautiful species so you can make a worthy decision. These Oscars are easy-to-care-for and require low maintenance, making them an ideal choice for novice and advanced fish keepers. 

The other thing that makes it a perfect addition is its long lifespan. The idea of owning and caring for them for a pretty long time is absolutely amazing and worth considering. Moreover, they are easy to breed in captivity, which is an added plus. 

So, what are you waiting for? Add these brilliant-looking species to your tank now, and we assure you that the experience will be rewarding. 

If we miss something important or you have any queries, please feel free to leave a comment below. We would be happy to hear from you!

Signs my Oscar Fish is Dying (Tank, Behavioral & Appearance)

Signs My Oscar Fish is Dying

The Oscar fish is a tough competitor in the aquarium world. Although generally hardy, the Oscar is susceptible to many diseases and parasites. You should be able to recognize if your fish has a disease or parasite in order to start treatment sooner rather than later.

To avoid worst-case scenarios and save them before it’s too late, here are signs my Oscar fish is dying and in need of immediate medical care.

How to Tell If My Oscar fish is Dying? 

The first thing to note is your Oscar’s appearance and behavioral patterns. Are there any sudden changes? Remember that no one fish is the same. 

While subtle changes may mean nothing, noticeable changes are cause for alarm. 

Apart from being visually sick, the aquarium also provides me with significant signs that my Oscar fish might be deteriorating.

Behavioral Changes of a Sick Oscar Fish

signs my Oscar fish is dying

Loss of Appetite

Fish spend most of their life eating; thus, this is a sure way to measure your Oscar fish’s well-being. 

Like other Oscar fish, my tiger Oscars are gluttons, and they tend to even beg for more after feeding. So, a decline in appetite, whether sudden or gradual, may mean that they’re distressed or ailing.

Loss of Awareness

I once had an Albino Oscar who loved showing off his colorful scales in his 75-gallon tank. He even kept re-arranging the rocks until they weren’t visually appealing anymore. 

Oscar fish are personable, so when you notice they start losing vitality, there might be something wrong. It’s best to find out the cause immediately. It may be the water temperature or their diet or a sudden change in their environment stressing them out. 

Loss of Balance or Buoyancy 

Buoyancy refers to a fish’s inability to control sinking and floating. Oscar fish tend to lie down to their sides on the bottom of the tank when agitated, and this is normal. What’s not normal is if they don’t shoot back up instantly or remain less responsive than usual once stimulated.

Oppositely, I have seen cases where they had trouble sinking, only floating almost at the surface of the tank. Sometimes, they even float upside down or on their sides. These are symptoms that usually point to a swim bladder disease.

Increased Respiratory Rate

Just like people, Oscar fish hyperventilate when in distress too. My veterinarian gave me some tips to check an Oscar fish’s pulse. You have to count the times their gill covers, their Opercula, move. Any hint of labored breathing or a respiratory ailment should be dealt with immediately.

Appearance Changes of a Dying Oscar Fish

Hole in the Head 

Hole in the Head (HITH) is one of the easily recognizable diseases of Oscar fish. The usual symptoms would be white sores on top of the head, around the eyes, or both.

Some other things to look out for are:

  • Deep cuts and grazes on the head and lateral line
  • Mucus coming out of its holes
  • Loss of appetite

I recommend consulting your veterinarian to find what kind of treatment your Oscar would need. For reference, I used Flagyl (metronidazole) to treat one of my Tiger Oscars.

Skin & Fins

If your Oscar develops tattering and blackening or reddening of its fins, including blood, then it is a cause for concern. These could be symptoms of Columnaris Disease, more commonly known as Fin and Tail Rot.

Other symptoms to check are parts of the fin are tearing off, the body looking slimy, skin having white spots, or behavioral abnormalities like appetite loss and sitting on the bottom of the tank.

‘Fish and Tail Rot’ is caused by bacterial contamination; thus, it needs antibiotics, or in worse cases, surgery. Ich, caused by a rapidly producing parasite, can be treated at home, but Aquarist must follow specific instructions. 

Also, if you notice white spots on the skin or gills, then this could be Ich or white spot disease,which is usually fatal if not promptly treated. 


I always look out for swollen or bulging eyes from my Tiger Oscars. It could be a sign of Popeye Disease caused by poor water management in the tank. 

Popeye disease, although treatable, can cause permanent damage like blindness in the affected eye.  

Body Shapes

Swollen stomach bumps, erratic swimming, a belly that appears bloated can spell several issues for your Oscar fish. It can range from constipation to Swim Bladder Disease to the more serious Dropsy.

While constipation may be better by improving diet, water conditions, and temperature, Swim Bladder Disease and Dropsy are more complicated. At-home treatment of dropsy is not often successful. Consult your local vet for advice on how best to handle this condition!

Tank Signs of a Dying Oscar fish

Cloudy Water 

Despite your efforts in cleaning the tank, the water remains cloudy. Why? One word: Bacteria. 

When uneaten food breaks down and decomposes into the water, it becomes a breeding ground for bacteria. It makes the water hazy because it’s full of bacteria. 

Initially, these bacteria are harmless, especially to the resilient Oscar fish. However, too much can cause distress to the Oscar Fish and make it fatally sick.

Author note: When setting up a new aquarium, it is common for the water to become cloudy. This happens because of beneficial bacteria that convert ammonia and nitrites into less harmful compounds.

Protein Foam 

Waste-causing protein is one of the more harmful bubbles in aquariums. The often-smelly foam can be from several reasons:

  • Dead fish – Dispose of fish debris that may have been from feeding
  • Dead plants – Little bits of tank plants that are decaying
  • Other Waste and left-over food – Often sitting at the bottom of the tank
  • Dirty filter – Buildup of remains caught by your filter

I always check small spaces like decorations where debris may settle and hide. Oscars are known for being messy eaters, so I recommend getting their extra aquarium filters.

Uneaten or Excess Food

An Oscar is an aggressive eater. If you can find food sitting on the bottom of the tank, then it might mean a decreased appetite for your fish, or you are giving them too much. 

Prolonged overfeeding and mismanagement of their diet can easily lead to many health complications. 

Dead Specimens 

Other than protein, decaying fish release harmful toxins. These include ammonia, which can harm tank mates. If the deceased fish died of an illness, it would be wise to observe its tank mates closely in case they develop similar symptoms.

After removing the fish, I recommend sanitizing all the equipment used. I also perform a deep clean of the tank for additional protection.

Final Thoughts

Oscars are a great fish for first-time tank owners to get. With careful attention and knowledge about their needs, you can prevent most of these diseases from happening in your aquarium!

I hope this article has helped. If you have any questions or feedbacks, feel free to contact me below.

Hole In The Head Disease in Oscar Fish (Causes, Symptoms and Treatments)

Hole In The Head Disease in Oscar Fish

Also known as the Velvet Cichlid or Tiger Oscar, the Oscar fish is a species of the Cichlid family that originated in the Amazon basin. 

Commonly found in South American markets, Oscars are labeled as non-native pet species in the United States. Typically found in green to dark brown colors, these fish are great ornamental species to have in your aquarium.

However, it is worth noting that this species is a little aggressive and needs special care. This includes being watchful of the hole in the head disease in Oscar since they are very susceptible to Hexamita infection. 

Want to know more about this disease? Keep reading then!

Causes Of Hole In The Head Disease In Oscar Fish

The root cause of the disease is yet to be pinned down, but there are several causative factors responsible for the infestation. 

Fish sense their surroundings using a cluster of sensory cells called neuromasts, which are mainly located near their head and lateral line holes. These receptive structures are prone to bacterial, protozoal, fungal, and chemical attacks. 

The symptoms don’t really occur in the presence of one causative factor and are observed only when there are two or more contributors. That said, some of the common causes of hole in the head disease in Oscar are:

Hexamita Infection

Do you know about this vile flagellate parasite? You might have heard about Hexamita in reference to intestinal tract infections. The infection isn’t just limited to humans or animals but extends to the aquatic kingdom as well. 

The protozoan initially infects the intestine and then slowly stems over the kidneys, abdominal cavity, gallbladder, and spleen. When the infection has spread sufficiently, the classic white lesions associated with the hole in the head disease start appearing.

You must have guessed by now; by the time these spots appear, the matter goes well out of hand. What makes it worse is that these lesions open up and ooze out tiny white threads containing protozoan larvae. 

It’s so uncomfortable even to read, right? Imagine your fishy going through all this. We also find it imperative to mention that these holes become susceptible to secondary fungal or bacterial infections and may lead to death in severe cases.

Therefore, you must start clinically treating your Oscar fish at first sight of this disease. 

Nutritional Imbalance In The Tank

The occurrence of the disease is also linked with vitamin or mineral imbalance in their habitat. Many aquarists have linked the frequent instances of disease with the increased biofiltration and overexploitation of carbon filters.

It is speculated that the filters remove integral elements from the water, which leads to the hole in the head disease. However, some people also argue that this imbalance of nutrients is an “effect” rather than a “cause” of the disease. 

Due to the presence of Hexamita in the intestine, fish stop taking in necessary minerals from water and start malabsorption. You can read the situation from both points of view.

Stressful Environment

The HIIH disease is also likely to occur if Oscars stay under high stress for a prolonged period. Stressful conditions weaken the immune system in fish and make them prone to several disorders.

Improper nutrition, unclean surroundings, overcrowding in the tank, and poor water quality are common stress inducers and can cause health problems. You must take care of these parameters, especially if you have old fish in your aquarium.

Signs Of Oscar Fish Hole In The Head

The most obvious sign of the syndrome is the characteristic white pitting-type lesions that occur on the head and body’s lateral lines. Now, the openings might not be obvious at first, but if you don’t initiate treatment or changes in the water, the situation is bound to get worse. The holes will enlarge and develop several other infections. 

Since Hexamita primarily affects the intestine, the initial signs of the disease can be observed by keeping a close eye on your fish’s eating habits. If your Oscar is experiencing a loss of appetite, it might be one of the first symptoms of the disorder. But this isn’t a conclusive sign as several reasons may cause appetite loss. 

The most reliable way to diagnose the disease is by identifying the white lesions during the early stages. 

Oscar Fish Hole In The Head Disease Treatment

We’ve been talking about the cause and the effects of the disease all this while. Now, let’s discuss how to cure it. 

Since the disease is induced by so many factors, the approach to curing it should be multi-faceted. If we map out, there are three main objectives that’ll help us get rid of the infection: 

  • Remove Hexamita from fish’s intestine
  • Improve the quality of water
  • Improve the minerals and nutrients in the water

The parasite can be treated by adding the antibiotic metronidazole to the tank water. It works wonders for treating bacterial and fungal infections. Along with that, you can add Kanacyn, Maracyn, and Furan. 

Closely observe the water quality of your aquarium and routinely adjust it as per the standards suggested for your species. You can improve the nutritional quality of your tank by adding lightly steamed broccoli or seaweed strips to the water. Following all these steps will help in the swift recovery of your Oscars. 

Final Thoughts 

Oscars are beautiful ornamental fish that can be slightly invasive in aquariums and require a lot of maintenance and care. If you have them in your tank, you know how notorious they can be at times. But regardless of that, they are adorable little creatures.

The species is prone to catch the hole in the head disease if not looked after well, so you need to be watchful for that. Even if your fish ever gets infected, you know how to treat it now!

What Do Oscars Eat?(& How Often to Feed Them)

What do Oscars eat

No aquarium is complete without the googly-eyed Oscar fish!

After all, their variety of vivid colors and patterns are too good to resist. From the patterned Tiger Oscar fish to the milky white Albino Oscar fish- there’s an “Oscar” for everyone!

However, like any other fish or pet animal, Oscar fish also require a proper diet to maintain a healthy and long life. So, you must be wondering: what do Oscars eat? Well, these good-looking guys are hardcore meat lovers! 

But, there’s a lot more to their diet, and this guide will help you understand what’s best and what’s not for Oscars. So, without further delay, let’s dive right in!

Best Food For Oscar Fish

Oscar fish have a very varied diet in the wild, so it is best to recreate it for healthy growth and development. This is possible by investing in a combination of high-quality and high-protein prepared foods, fresh fruits and vegetables, and tiny pieces of meat.

You can top it off with live food once in a while. However, most hobbyists recommend staying away from using store-bought live organisms.

Pellet and Flakes

Readymade food is hands down the most convenient option for feeding any species of fish. They are easily accessible, require no preparation, and fulfill the nutritional needs of aquarium fishes. Depending on your preference, you can opt for pellets or flakes.

Prepared food like pellets and tablets are an excellent option for Oscars since they create no mess and do not cause cloudiness in the tank. Or, you can split wafers into three equal parts and feed the Oscars one by one. These food items are easy to swallow whole, even for juvenile Oscars.

Flakes, on the other hand, can get messy and settle down at the bottom of the tank. This can, in turn, degrade the quality of water.

Opt for well-known brands like New Life Spectrum and Hikari for fast growth and vibrant coloration.

Frozen Foods

Frozen food for fish mainly consists of seafood. You do not have to worry about which type of seafood would work best because anything from shrimps to squids is suitable for feeding Oscars. However, ensure that you alternate between different varieties of seafood and never overfeed just one type.

Small seafood formulas like bloodworms and brine shrimps can be fed to tinier species of Oscars. More oversized food items will only cause a mess!

Live Food

Wild Oscars are mostly found in the tropical and subtropical regions of South America, wherein they consume live insects, larvae, and smaller fishes. However, if you maintain a tank of Oscar fish or have some in an aquarium, live feeder fishes should be fed in moderation.

While live food sounds like a nutritional option for Oscars, it is quite the opposite. For instance, feeder fish are mass-bred in the worst conditions. Since these feeder fish are given the cheapest and lowest quality filler foods, they offer no nutritional value to Oscars. 

Additionally, this option is more expensive and inconvenient as live food does not have a long shelf life. However, if you want to treat Oscars once a week, we suggest crickets and worms from your backyard or farm.

Or, if you purchase live fish food in bulk, make sure to quarantine the lot to prevent disease transmission and water contamination. 

Can Oscar Fish Eat Human Food? 

Besides the food items mentioned above, Oscar fish can enjoy other human food like fruits, vegetables, and some nuts. These food items provide high protein internally and rich saturation externally. 


Good ol’ green vegetables are not just recommended for you, but for Oscar fish too! Peas, lettuce, green beans, cucumbers and carrots are incredibly nutritious choices for the fish.

However, make sure you cut the veggies small enough for them to eat. For this reason, peas are your best bet as most fishes can swallow them like pellets.


Fruits like bananas, apples, mangoes, and sweet melons make great treats for Oscar fish. But, as mentioned before, cut them into bite-sized pieces and feed them in moderation.

As you see, Oscar fish will never say “No” to good food! This will lead to digestion problems which can worsen their health. So, avoid overfeeding your Oscars at any cost.

How Often To Feed My Oscar Fish?

In continuation to the previous point, seeing your Oscars eat anything you throw at them isn’t a sign of healthy eating. If need be, they can gobble up their tankmates too!

The amount of food and the frequency of feeding depends on the age and size of your Oscar fish. For your reference, we’ve broken down some pointers according to the age and size of the fish, but note that these are merely estimates, and not fool-proof methods. Let’s take a look…

Juvenile Oscar Fish

Young Oscars are usually 1.5 to 3 inches in size, so feeding them twice a day is sufficient for fast growth. Most fish tank owners prefer feeding baby Oscars just until their stomachs are slightly bloated.

You can feed them once in the morning and then in the afternoon or early evening. However, do not rush the process. Give them time to swallow the food before you dunk in some more. If served with way too much food, Oscars tend to spit the food particles and move to the other. Talk about being greedy!

Additionally, try to add variety to their diet as that will help develop their taste, which, in turn, will help you later in feeding them as adults.

Adult Oscar Fish

If the fish are 4-6 inches in size, you can feed them daily but alternate the frequency between once a day to twice a day. This will not only ensure complete nutrition but also control their appetite. 

In most cases, a fully-grown adult Oscar fish is about 7-8 inches in size unless they are stunted. This is the time when you should watch their weight and feed them accordingly. However, just because one of them looks overweight does not mean you reduce its food intake drastically. If you do, the poor tankmates will have to pay with their lives!

For best results, adult Oscar fish should be fed once a day on alternative days. If you wish to feed them more than once, limit the practice to twice a week.

Best Oscar Fish food for color?

Some foods can help to enhance the color of your Oscar fish. If you want a bright red, orange, or green appearance for your pet, one should look out for Astaxanthin-rich food such as shrimp and krill.

Frozen peas are my secret weapon when it comes to Oscar feeding. Without going on and on about all this fancy scientific stuff (too much), but I’ll keep it simple: they work! I have my own Oscar, and he is so much more colorful and energetic because of these.

All you need is some frozen peas from the grocery store, and remember to keep them frozen available at all times, right up until it is time to offer a treat! When the time comes for feeding, simply remove a few, rinse off under cold water, and offer one at a time into your tank.

Pro tip: If it's your first time to feed frozen peas to your Oscar, he may spit them out. Eventually, he will take them—and love the taste!

What do Baby Oscar Fish Eat?

Opt for small-sized pellets, flakes, frozen/ fresh veggies, fruits, or live food for baby Oscar fish. As long as the food particles are small enough to swallow, you should be good to go. 

Again, keep in mind that Oscars are gluttonous beings, even as babies! So, no matter how well they eat, always check the food portions and do not overfeed.

Best Oscar Fish Feeding Rules?

By now, you know that Oscars can enjoy a variety of food items, but there are certain feeding rules you must keep in mind for their overall development. 

Avoid Fatty Items

First off, there is a high risk of obesity among Oscars, thanks to their gluttony. This can result in unhealthy amounts of fats in their bodies or fatty liver issues. Hence, live feeder fish are not recommended as a staple diet. Moreover, you should avoid meaty parts of chicken or any other non-vegetarian option.

Free From Chemicals

Oscars love a good crunch, making insects the most suitable food item for them. However, ensure that the insects you pick for the fish were not exposed to chemical pesticides and fertilizers. 

Astaxanthin For Better Color

There are various types of Oscars out there, with Tiger Oscar Fish and Albino Oscar Fish being the most common ones. While these fishes are blessed with attractive colors and patterns, their food plays a huge role in enhancing their coloration.

Astaxanthin is a compound found in skrill, river fish, and other red-colored aquatic organisms. So, incorporating them into the daily diet of your Oscars is a must.

Among readymade food, Tetra Tropical 16159 is rich in Vitamin C and color-enhancing nutrients, making it ideal for adult Oscar fish. Sera 411 is also popular for Tiger Oscar Fish as it provides a healthy combination of haematococcus algae and Krill, perfect for enhancing the fiery red color of this species.


If you are raising baby Oscar fish, it is best to add lots of variety to their diet at an early stage. Besides ensuring a well-rounded meal, this allows them to adapt to different food types, making it easier for you to pick food once they get older.


We hope that this guide gives you a better idea of what Oscars eat and how you should feed them.

Other than their stunning looks, Oscar fish are known for their intelligence, too. It is said that they can even recognize their owner! So, as a responsible caretaker and hobbyist, you should feed them highly nutritious food in controlled portions. In return, you get beautiful, healthy, and happy fish.

With that, we come to the end of this informative guide. Until next time…Happy feeding!

How Long Do Oscars Live? (In Captivity & Wild)

How Long Do Oscars Live

Thinking about keeping a pet Oscar in your home aquarium? Here’s all you need to know about their life span. 

The Oscar fish is part of the cichlid family and are known by many other names – Marble Cichlid, Red Tiger Oscar, Velvet Cichlid, etc. These fish have a typical life span of 10 to 20 years in the wild. However, if you are thinking about keeping them in a tank, there are a couple of things to know. 

Read on to find the answer to “how long do Oscars live?”

How Long Do Oscars Live In Captivity?

Those thinking about keeping Oscars in captivity may be wondering how long they can live in a tank. Given the right environment, food habits, care, and tank conditions, these fish can live for 8 to 12 years in captivity.

That being said, some Oscars are known to live for up to 15 years in captivity if they are cared for properly. Those who want to introduce Oscars to their home aquarium must provide the right conditions and diet for them to thrive for over a decade.

If you plan on introducing Oscars to your current tank, there are a few things to be careful of. As such, you should research thoroughly to find suitable tank mates that Oscars can live with.

How Long Do Oscars Live In The Wild?

Although Oscars live for about 8 to 12 years in captivity, these beautiful, lively fish can live up to 10 to 20 years in the wild. Moreover, they can grow to be very large fish, growing up to 11 to 12 inches. Some Oscars, however, can grow even larger, measuring up to 16 inches!

Keep in mind that Oscar fish are quite aggressive and territorial. In addition, they are known for killing other fish, so some Oscars may die prematurely due to aggressive behavior.

How Long Can Oscar Fish Live Without Food?

When you think of getting a new pet, one of the first things you need to consider is a consistent feeding schedule. That said, it may be surprising to know that Oscars can live without food for up to two to four weeks!

Keep in mind that this depends largely on their age, temperament, and size. While baby Oscars can live for about two weeks without food, adult Oscars are able to survive for up to four weeks without food.

That being said, we do not recommend testing their limits if you plan on introducing them to your tank. Instead, ensure that you maintain a consistent feeding schedule and give them high-quality food such as pellets, flakes, and occasionally live food. Again, it is best to speak to an expert or research well about the right foodstuff to feed your Oscars.

How To Increase Oscar Fish Lifespan

It’s obvious – when you get a new Oscar as a pet, you would want it to live for as long as possible. However, to make that happen, you need to maintain a rigorous schedule, so they are happy and thriving. Without this, they may start to turn white. However, do not confuse them with Albino Oscars, which are naturally white due to their lack of color. 

Buy A Healthy Oscar

Most pet owners try to find good breeders so they can adopt or buy healthy pets. This is essential, as unhealthy animals or fish can have a host of diseases and health problems later in life. Treating them may be an option, but it is always best to get healthy baby animals.

Ensure that you buy a healthy Oscar from a reputable breeder or pet shop. This will ensure that your pet has a happy, healthy, and long life in your home.

Keep Them In A Big Tank

Oscar fish can grow to be at least 11 to 12 inches long. Moreover, some Oscars can grow even larger, so you need to ensure that you have an adequately large tank for them. 

As such, you will require a 75-gallon tank for your adult Oscar. If you have more than one Oscar in the tank, it may be best to increase the tank size to up to 100 gallons. Furthermore, ensure that you maintain good tank hygiene and set up the tank appropriately.

Have A Filter

It is imperative to have a good filter system in the Oscars’ tank to ensure that they are healthy. Make sure that you research thoroughly and purchase the right filter for the tank size. Furthermore, you need to clean and maintain it regularly to keep the water from becoming toxic. This will help your Oscars grow and thrive.

Keep The Tank Clean

It is crucial to keep the Oscars’ tank clean; otherwise, they are prone to catching infections and diseases. Make sure that you clean the tank, filter, and other decorative items in the tank regularly.

Getting A Balanced Diet

The most important thing to take care of is your Oscars’ diet. It is essential to feed them high-quality fish food and live food. Ensure that the live food is contaminant-free so it doesn’t adversely affect the Oscars’ health.

Furthermore, maintain a proper feeding schedule and create a healthy habitat. Doing the bare minimum can help increase your Oscars’ lifespan, letting them live happily for up to 8 to 15 years in your tank.


How Long Can Oscars Live In Cold Water?

As such, Oscars can tolerate low temperatures of up to 55° Fahrenheit. That said, it is best to maintain proper tank temperature; otherwise, they may perish within a few weeks or months.

How Long Can Oscars Live Without A Filter?

Oscars can survive for about three days in a tank without a filter.


Now that you know everything about Oscars and their lifespan (and how to increase it), you are ready to be a pet parent.

As with any animal or fish, ensure that you maintain a healthy living condition for your Oscars to thrive. Moreover, research adequately to find the right diet and tank conditions for them. 

That’s all for now; we hope you enjoyed reading this guide. If you have any more questions, feel free to leave a comment below.

Until next time, pet parent! 

Oscar Fish Tank Size (The Wrong Size Can Kill Your Fish)

Oscar Fish Tank Size

Oscar fish are known for their large size, beautiful color, and loyalty to their owners. 

They are among the few rare fish that acknowledge and remember the hand that feeds them. In return, all the Oscar fish asks for is regular feeding, amiable tank mates, and a well-maintained tank.

Since this freshwater species can grow up to 18 inches in length, it’s crucial to provide them a large enough space to swim freely. Needless to say, responsible first-time owners often wonder what the ideal Oscar fish tank size is. 

Here are a few things to remember before buying an aquarium for your beloved Oscar fish.

The (False) Recommended Oscar Fish Tank Size

Don’t believe everything you read on the internet, especially when it comes to pet care. For example, a few online sources claim that even 30-gallon tanks are suitable for Oscar fish. However, any experienced aquarist will agree that anything around 75 gallons is not recommended.

What’s The Minimum Tank Size For Oscar?

Whether you are bringing home a Tiger Oscar, an Albino Oscar, or any other variation of the Oscar fish, all of them have the potential to grow to a large size. That being said, aim for a 75-gallon tank as the minimum tank size for a single Oscar. 

What Size Tank Do I Need For 2 Oscars?

For most aquarists with a single Oscar fish, a 75 to 90-gallon tank is the norm. Although some aquarists have had luck keeping two Oscar fishes in a 90 to 100-gallon tank, this poses the risk of diseases, such as Hole in Head (HiH) and Lateral Line Erosion.

After all, a large size tank is not only meant to provide space to move around. In fact, the voracious appetite of Oscars leads to an exponential buildup of fish waste. This bioload further produces ammonia, one of the most common culprits of poor water quality in aquariums.

Moreover, leftover scraps of fish food break down into nitrate compounds that can prove to be toxic for any fish. As a rule of thumb, ensure that nitrate levels stay below 20-30PPM at all times.

With all that said, a 75 to 90-gallon tank can work perfectly fine during the grow-out period of two baby Oscar fish. However, once these have matured and reached 10-18 inches in length, you will need to place them in a 150 to 180-gallon tank. 

In fact, you can start your own cichlid fish tank by introducing a few other cichlids to the tank once the pair of Oscar fish is well-settled. 

Will An Oscar Outgrow Its Tank?

Based on anecdotal evidence, it has been observed that an Oscar fish witnesses stunted growth when put in a tank that is too cramped. Although it may seem like the fish is adapting to its surroundings, this is actually a sign that there are problems with its environment. Moreover, some fish do grow to their potential size, albeit at a much slower pace.

Nevertheless, it is essential to remember that the discrepancy in their growth rate is not a result of the tank size itself but because of poor water quality. In fact, choosing a small tank for a large fish, such as an Oscar, is akin to making the fish swim in its own waste.

Even with a sound filtration system in place, nitrate, nitrite, and ammonia in a small tank reach harmful levels. This not only leads to stunted growth but also drastically reduces the lifespan of the fish.

At the same time, we cannot completely disregard the fact that a smaller size tank perhaps leads to tiny Oscars due to insufficient space for natural movement. Either way, a bigger tank for an Oscar will lead to more beautiful and active fish that are a delight to have around.

Can A Tank Be Too Big For Oscar Fish?

When it comes to picking a fish tank size for an Oscar fish – the bigger, the better. In fact, the Oscar fish is native to the waters of the Amazon river, which is considered the most extensive river globally, in terms of the volume of its flow.

Needless to say, no tank in the world can be too big for the Oscar fish, which thrives in a vast expanse of water when in the wild.

However, it is essential to note that the Amazon river lies in the tropics of South America, and the warm waters are well-suited for the fish. Therefore, most aquariums will require a heater to provide a comfortable water temperature of about 70-80 degrees Fahrenheit.

Can An Oscar Live In A 10, 20, or 30 Gallon Tank?

In the wild, Oscar fishes grow up to a length of 18 inches, and in captivity, they may peak at about 10 to 14 inches. Needless to say, a growing Oscar will require much more than a 10, 20, or 30-gallon tank for a healthy and long life.

The ideal fish tank would be 4ft. long and 2ft. wide, and can hold at least 75 gallons of water. Be advised that this is a minimum requirement for a single fish. If you are planning to raise a pair of Oscars, make sure to double the volume of water and the size of the tank for optimal growth and health


While Oscars are an amiable fish, they are undoubtedly a high-maintenance species that require at least a 75-gallon tank per fish. Even buying the right fish tank size is not enough – proper care and maintenance of the tank itself are crucial. 

This is in addition to regular water changes and fitting the aquarium with necessary devices. Filtration systems, in particular, are non-negotiable when dealing with Oscars, which produce a lot of fish waste. 

Moreover, a large tank that holds a greater volume of water facilitates dilution of the fish waste and aids the filtration systems. To sum it up, an ideal fish tank size leads to better water quality and ample space for movement. This, in turn, provides Oscar fish a long and happy life.

How Big Do Oscars Get? (In Captivity & Wild)

how big do Oscars get

Oscars are large and messy, and so much more. 

Many aquarists love to have them around the house because of their intelligence and interesting personalities. In fact, they are lovingly called “river dogs” because of their loyalty and ability to recognize their owners. 

That being said, Oscars have big personalities, which means they can be moody, aggressive, calm, happy – all on the same day. To keep aggressive behavior at bay, it’s crucial to put Oscars in a tank that simulates their natural habitat and is large enough for them. 

And so, the question arises, “How big do Oscars get?”

How Big Do Oscar Fish Get In Captivity?

In captivity, full grown Oscars can measure up to a maximum of 12 inches – a healthy 10 inches being the norm. However, their healthy growth depends on various factors, such as tank size and nutrition. In fact, keeping an Oscar alive requires suitable environmental conditions. If done right, this species of fish can live to be as old as 20 years old. 

How Big Do Oscars Get In The Wild?

Most wild Oscars will be about 18 inches in length and weigh around 3lbs in the wild. when they are fully mature. However, these numbers may vary according to the environmental conditions and specific breed. In fact, the famous Red Tiger Oscar cichlids, most notable for their large dark bodies and golden spots, are mostly found thriving in the wild.

How Fast Do Oscar Fish Grow In Captivity?

Some aquarists claim that their fish went from 4 inches to 10 inches in a matter of four months, whereas others recorded a growth of 1.5 inches in the same period. Yet another pet owner noticed that their Oscar fish was fully mature within two years, which is when the fish revealed its gender. Needless to say, there is no fixed growth rate of Oscars.

6 Factors that Determine How Big Oscar Can Get

When the maximum size was measured at maturity, most of the Oscar fish in captivity were significantly smaller than those in the wild. Needless to say, the Oscar fish thrives most in its natural surroundings in the slow-moving waters of the Amazon basin. 

At the same time, they can live adequately healthy lives in a desirable environment even in captivity. In the end, the growth of an Oscar fish depends on the size of the tank, filtration, and food provided. 

Tank Size 

Oscars are generally not considered to be beginner fish because of the large aquarium that they require. While some online sources recommend a 40-gallon tank for a single Oscar fish, that number should, in fact, be doubled. As a rule of thumb, 75 gallons should be comfortable for a single Oscar fish, whereas a minimum of 100 gallons should be enough for a pair.


When it comes to large fish with a big appetite, don’t be surprised if they leave a large bioload behind. Therefore, it is highly crucial to have a proper filtration system that can keep the aquarium water waste-free for the most part.

A combination of a canister filter and a HOB (hang-on-back) filter will provide sufficient filtration, as long as the aquarium is large enough to dilute the waste. Needless to say, a small tank is a recipe for murky waters, which can cause illness or prove to be fatal to the Oscar fish


In the wild, Oscars are predatory fish that primarily feed on insects and other small fish. Live food, such as worms, crayfish, feeder fish, and insects, is suitable for those fish in captivity. Alternatively, Oscars devour thawed meat-based frozen fish foods with much delight.

Water Condition

The Oscar fish requires the same tank water conditions as most freshwater species. So, begin preparing the aquarium by placing an under-gravel filter and 3 to 5 inches of substrate at the bottom.

After this, apply a conditioner or let tap water stand for at least 24 hours before pouring it into the tank. Since Oscars are highly sensitive to temperature, use a heater to replicate the warm water of the tropics. Ideally, the water temperature should be 77°F, but anywhere between 74 and 81°F should be comfortable enough.

Tank Mates

Placing a smaller fish with Oscars is a bad idea since they will gobble up any that fits into their mouth. These predatory fish are notorious for being aggressive not only to smaller fish, but also to their own kind. 

In fact, any timid fish will get stressed out by the aggressive antics of this fish. On the other hand, confident fish, including types of catfish and cichlids, will likely get along with Oscars.

You might be interested: 7 Best Oscar Fish Tank Mates (Compatible And Safe)

Tank Maintenance

Given their large size and food intake, Oscars are likely to produce larger amounts of ammonia, which is a primary component of fish waste. While chemical filtration is necessary to remove toxins and keep the water clean, regular water changes are also absolutely required.

Furthermore, if you plan to use a submersible heater, ensure that it is shatter-proof as Oscars are destructive. What’s more, they delight in jumping out of their tanks, so remember to leave the aquarium shut at all times.


How Fast Does A Baby Oscar Grow?

Some baby Oscars can grow from half-an-inch to one inch a month until they are 10-18 inches. On the other hand, some may never even grow at all. In the end, it’s their living conditions and nutrition that will decide the growth rate.

Do Oscars Grow To The Size Of The tank?

If the tank’s size is appropriate and is filled with at least 70-75 gallons of water, it is unlikely that the Oscar will grow to that size. At the most, these species of fish peak at 18 inches in length.


To sum it up, Oscars are relatively high-maintenance fish with a voracious appetite and an aggressive streak. However, with proper care, they can grow to be large 10 to 18-inch fish that are magnificent to look at. 

In fact, variations and fancy Oscars, such as the albino Oscar and Lemon Oscars, are some of the rarest and most expensive fish in the sea and aquariums. 

That being said, taking care of one may prove to be challenging if you wish to see it grow to its maximum potential. But, at the same time, an Oscar’s beauty, mischief, intelligence, and loyalty are what make it so valuable. 

Do Oscar Fish Have Teeth? (And Do They Bite?)

Do Oscar Fish Have Teeth

Are you an aquarium enthusiast thinking about introducing Oscar fish to your tank? Here’s all you need to know about their teeth. 

When you hear the words “fish with teeth,” you immediately think of deadly sharks and piranhas. However, are Oscar fish as dangerous as these deadly creatures, or can you keep them in a tank with other fish? Don’t worry; we’re here to help you. 

Do Oscar fish have teeth or do they bite? Take a look at our short but informative guide to know all about it. 

Do Oscar Fish Have Teeth?

Getting right to the point – yes, Oscars have teeth. However, whether you need to worry about keeping them in your tank with other fish depends on several factors. Although Oscars have teeth and can nip or bite down on flesh, it’s not too dangerous if they are well trained. Moreover, these fish do not have vicious bites like their cousins – Piranhas and Sharks. 

That said, Oscars’ teeth are sharp enough to bite through and chew on the flesh of other fish and animals. If you plan on introducing Oscars to your aquarium, consider getting baby Oscar fish. You can train them not to bite too hard to draw blood, which can be helpful as they grow into beautiful adult Oscars.

How Many And What Kind Of Teeth Do Oscar Fish Have?

Oscar fish have two sets of teeth. However, they do not have any teeth on their jaws, unlike humans and other animals. The pharyngeal teeth, as the name suggests, lie at the back of their throat.

The other set of teeth are located at the back of their mouths. These teeth are not sharp enough to cause significant injury to human flesh, but their bites and nips can surprise you or hurt slightly.

Furthermore, Oscar fish are primarily suction feeders. This means that they suck their food into their mouths and then chew it at the back of their mouth and throat, before ingesting it. They do this with their mouth closed, so it’s unlikely that you will be able to see the process.

Will My Oscar Fish Bite Me?

Whether the Oscar fish will bite you or not depends entirely on their temperament and how you have raised them. As such, even vicious dogs and other animals can be trained by their owners not to bite. The same theory applies to Oscar fish. 

It helps to get your Oscar fish at an early stage in their lives as it is easier to train them. Although species like Tiger Oscar fish are known to get quite large and even bite other fish, their behavior is mostly territorial. 

So, although your baby Oscar fish may tend to bite or nip your fingers, they can effectively be trained not to bite too hard. 

Can You Hand Feed Oscars?

Hand-feeding Oscar fish is a great way to teach them not to bite aggressively. However, this works best if you practice it with baby Oscar fish rather than full-grown adult Oscars.

You can attempt to hand-feed your adult Oscars as well. That being said, keep in mind that they may try to bite your fingers sometimes.

Although the bite may come as a shock, it is generally not hard enough to injure you critically. However, keep in mind that aggressive bites may draw blood, so be careful when hand-feeding Oscars.

Are Oscar Fish Aggressive And Dangerous?

Yes and no. Oscar fish are generally friendly with humans and will not bite unless they feel threatened. However, these fish are extremely territorial and are known to kill other fish for space in the tank. Although these fish can exhibit dangerous and aggressive behavior, you can keep them as pets as long as you provide them with proper training.

Since Oscar fish belong to the cichlid family, they exhibit typical behavior and characteristics shared by other fish of this family. So, your Oscar fish may be territorial, may bite, but will typically not show aggression towards their owners.


Any aquarium enthusiast knows the immense joy and pleasure of introducing new fish into their tanks.

While Oscars can make excellent pets, it is advisable to train them from an early stage. Furthermore, ensure that you provide your Oscars with a healthy, balanced diet. This should slightly reduce their tendency to nip and bite, as many Oscars (and other animals) will exhibit this behavior due to hunger.

Make sure that you contact a professional, qualified breeder when bringing your Oscar fish home. Also, you will need to provide a tank that is large enough to accommodate adult-sized Oscars.

Best of luck with your new pets!

7 Best Oscar Fish Tank Mates (Compatible And Safe)

Oscar Fish Tank Mates

Oscar fishes are notorious killers and playful creatures – the perfect combination of stunning and troublesome. 

These tropical freshwater inhabitants are not the friendliest and are eager to devour or bully fishes that come their way. So, most aquarists wish to add a bit more color and spark to their aquarium and look for a suitable Oscar fish tank mates.

In this guide, we will look at the fish types that can be excellent tank mates for your Oscar and some species that don’t. So, without further ado, let’s dive right into it!

Can Oscars Live with Other Fish?

Yes, Oscars can live with any sort of tankmate (smaller, less aggressive fish) if you set up a minimum 100g tank. Sorry tank mates and tank size can’t be exclusive from one another.

Do Oscar fish need tank mates? Oscars do not necessarily need tank mates, but keeping other fishes around them can make them more sociable since they are inherently hostile. However, they are highly territorial, so make sure you keep them in a large tank so that both fishes get adequate space to thrive. 

A single Oscar will need a minimum tank capacity of 55 gallons, but that’s rarely recommended since it provides a tiny swimming area. However, as they grow slightly bigger, you will need to shift them to a 75-gallon tank. Some inexperienced aquarists make the mistake of putting another fish along with the Oscar in a 75g tank. This is a colossal mistake and negates the chances of either of the fishes thriving. Remember that for a tank that less than 100 gallons, a single Oscar is enough. 

For a 100g tank, you can have an Oscar with a school of Silver Dollars. However, if you want to keep two Oscars, then you will need a minimum tank capacity of 125 gallons. Usually, unless they grow up together, it is nearly impossible for two Oscars to live side-by-side, given their aggressive nature. 

You’ll need a tank with a minimum capacity of 120-125 gallons if you want to place any large-sized fish with your Oscar. 

Fish to Avoid Keeping with Oscars

Here are a few fish types you need to avoid while looking for an Oscar tank mate:

Too Small

Oscars are hostile creatures that will eat any fish small enough (less than 6-inches) to fit in its mouth. So, always look for fish that is larger than 6-inches. 

Timid or Delicate

An Oscar tends to bully its tank mates, so you need an equally aggressive creature. On the other hand, delicate and shy fishes like Discus need a quiet environment to flourish and will not compete for food with an Oscar.

Small Catfish

Small Catfishes have spines on their fins that will prove to be a danger to the Oscar if swallowed and can kill it.

Fishes That Need Clean Water

Oscars are pretty messy, producing a high amount of Nitrates. Thus, fishes that require pristine water conditions cannot survive in Oscar tanks.

Pro tip: Stick with south American fish, not central American, Central American fish will be too aggressive.

The Best Oscar Fish Tank Mates In A Tank (125g or Bigger)

While looking for a tank mate for your Oscar, ensure the tank is large enough to house both fishes. A Tiger Oscar grows up to 18 inches, whereas an Albino Oscar will become 14 inches long. Therefore, you will need a tank of 125 gallons or more to give adequate space to both the fishes. 

Out here, we have listed the best tank mates for your Oscar. So, let’s take a look!

Ornate Bichir

ornate bichir

Most Bichir species are wonderful tank mates for Oscars, but Ornate Bichirs (Polypterus ornatipinnis) are usually preferred because of their unique eel-like bodies and large size. Native to Central and East Africa, these air-breathing creatures occupy the lower regions of the tank and do not interfere with Oscar’s movement in the mid-region.

Although they are predatory, their targets are usually smaller fishes. Since Oscars are pretty large, Bichirs pose no threat to them and vice versa. Thus, if you choose to keep Oscar and Bichir in the same tank, ensure they are of the same size.

Ornate Bichirs can grow up to 24-inches, so remember to keep them in a large tank with a lid since they are active jumpers.

Scientific Name:Polypterus ornatipinnis
Care Level:Moderate
Color Form:Tan
Temperature:77-83° F
Minimum Tank Size:180 gallons

Gold Severum Cichlid

Gold Severum Cichlid

Bright colored and stunning, Gold Severum Cichlid is more peaceful than any of our other recommendations and can thrive in community tanks. They stay in their territory (usually behind rocks or other tank ornaments) and can gel with different non-aggressive Cichlids, Scavenger Catfish, and Plecos, besides Oscars.

So, if you have a tank large enough to keep more than two fishes, Severums will be a fantastic choice. Moreover, they grow up to 8-inches and are strong and combative enough to stand up to Oscars, if necessary. 

Also, their water parameters are similar, and you can keep the temperatures anywhere between 73-77°F.

Scientific Name:Heros severus
Origin:Amazon, Northern South America
Care Level:Moderate
Color Form:Tan, Yellow
Temperature:73-77° F
Minimum Tank Size:55 gallons

A School Of Silver Dollars Fish

Photo: David441491

Silver Dollars are schooling fishes that swim as a group in the open, thus signaling the absence of any predator. This can be reassuring for your Oscar, who is put at ease and becomes less hostile.

Besides, they have a roundish and laterally flattened body, resembling a silver coin that makes them appear much larger than their standard 6-inch size. As a result, these fishes will not fit in Oscar’s mouth and can easily survive in the tank with it.

Although some Silver Dollars are semi-aggressive, most of them are pretty mellow and do not do well individually. Thus, it is best to keep at least 4 to 5 of them together at all times.

Scientific Name:Metynnis argenteus
Care Level:Easy
Color Form:White
Temperature:72-77° F
Minimum Tank Size:30 gallons

Chocolate Cichlid

Chocolate Cichlid
Photo: cichlid.bros

Native to Southern America, Chocolate Cichlids are easy-going creatures and have the same water and food requirements as Oscar fishes, making them a suitable choice for tank mates. 

They grow over 12-inches long and are exceptionally calm compared to most Cichlids their size. You can keep them in a community tank with most South American Cichlids, Characins, or Catfish. 

It is usually safe to place Chocolate Cichlids and Oscars together since they are nearly the same size and do not threaten each other. 

Scientific Name:Hypselecara temporalis
Origin:Captive-Bred, Peru
Care Level:Moderate
Color Form:Brown, Orange, Red, Yellow
Temperature:76-82° F
Minimum Tank Size:70 gallons

Green Terror

Photo: lkmathew

As the name suggests, Green Terrors are known for their aggressive behavior and metallic green and blue colors. They can grow up to 12 inches, almost the same as Oscar fishes, making the chances of being eaten by Oscars negligible. 

Like Oscars, they belong to the Cichlid species of fishes and can be even more hostile than them, especially during the spawning season. However, the aggression declines over time, especially if the Green Terror is slightly smaller at the start. 

That said, sometimes, these two fish types do not get along, and in such cases, you need to have a backup plan in place. The best you can do is shift the Green Terror to a separate 55-gallon tank. 

Scientific Name:Andinoacara rivulatus
Origin:South America
Care Level:Moderate
Color Form:Blue, Green, White
Temperature:72-80° F
Minimum Tank Size:50 gallons

Firemouth Cichlid

Photo: threefingeredlord

Firemouth Cichlids are hardy and moderately aggressive, preferring to avoid any conflicts rather than facing them headlong. So, make sure you have sufficient ornaments and rocks in your tank to give this creature ample hiding space. Although they usually flee when faced with aggression, they can counter the hostility if necessary.

Since Firemouth Cichlids grow over 6 inches, Oscar fishes can’t eat them. Besides, their food and water requirements overlap, thus reducing the burden for you.

Scientific Name:Thorichthys meeki
Origin:Farm Raised, USA
Care Level:Moderate
Color Form:Blue, Red
Temperature:70-75° F
Minimum Tank Size:30 gallons

Black Convict Cichlid

Black Convict Cichlid
Photo: shutterbusterbob

Another variety from the Cichlid species, Black Convicts are proactive and aggressive. They create a territory for themselves inside plants or caves and often stay here. Thus, they will seldom cross paths with your Oscar fish, minimizing the chances of any conflict.

Moreover, they grow up to 6 inches and hence are unlikely prey for Oscars. Given their aggressive nature, they can stand up to Oscars, when necessary, as long as both the fishes are of similar sizes. That said, we recommend purchasing and raising them together. This will guarantee minimal hostility.

Scientific Name:Archocentrus nigrofasciatus
Origin:Farm Raised
Care Level:Moderate
Color Form:Black
Temperature:68-73° F
Minimum Tank Size:30 gallons


We hope you now have a good idea about the fishes that can live with your Oscar and the ones that can’t.

scar fishes are energetic, intelligent, and easy to raise as long as you provide the ideal living conditions and a spacious tank. Of course, like most other Cichlids, they have a prickly nature, and you need to be vigilant if you choose to keep them with tank mates.

That’s all we have for you today! Remember, Oscars are fascinating and lively creatures as long as you are patient and attentive.