Oscar Fish Care Guide Best Tank, Lifespan, Diet and Breeding

By Eddie Waithaka @aquariawise

Oscar Fish Care Guide Best Tank, Lifespan, Diet and Breeding

Oscar fish are intriguing cichlids to keep and possibly some of the most intelligent aquarium species. Plus they are beautiful especially if you love big guys in your tank.

Another mind-blowingly amazing trait is they can be hand fed. If you are their prime carer, they will even recognize you and offer boundless interactions.

On the flip side though, Oscars are quite feisty hence don’t make good tankmates unless they are kept with bigger, passive fish. Also, though not fussy feeders, they are quite messy and need constant cleaning.

They are native to the South American Amazon basin, Guyana and Suriname. Oscar fish are tropical freshwater species with great affinity to slow-moving white water habitats.

When fished in the wild, they make edible species, but a couple of ornamental Oscar fish have been developed for aquariums. Which include forms with greater intensity of red marbling across the body, albino, leucistic, and xanthistic forms.

Therefore, in the context of this article, we’ll majorly focus on the life, types, care and breeding of aquarium Oscar cichlids, sometimes called tiger, velvet or marble cichlids.

Oscar Fish Overview

Oscar fish are the most popular cichlid in fish keeping, with a couple of ornamental varieties available.

In the wild, they are typically darkly colored with yellow-ringed spots on the caudal and dorsal fins. However, in aquariums, the most common have black bodies with bright red striped colorations and are sold in pet stores as Tiger Oscar fish.

The other common types have a dark base color and red-solid coloration on the body and are sold under the trade name Red Oscars.

Other variations, almost as common, are Albino Oscars which are white with red-orange translucent eyes, at times baring pale blue or lemon yellow shades.

Oscars have a long oval body with dorsal and anal fins extending along the body to the caudal fin, which then forms a fan at the rear.

They can grow up to 18 inches in length, but on average they’ll grow 12 inches at three and a half pounds in weight. They also burgeon exponentially with a baby Oscar fish that’s about an inch growing to eight inches within a year. Which means its best advised only aquarists with big tanks keep velvet cichlids.

Also, Oscars are territorial and known to get aggressive when housed with other species. I, therefore, recommend you keep them in a species only aquarium.

Their preferred and optimal temperature is anywhere between 74°F to 81°F and a pH between 6.0 and 8.0.

Oscars will eat a large variety of food, but it’s crucial to maintain a balanced diet. Mealworms and bloodworms are an excellent choice that aligns to their natural diet. Though, their food should also consist of a balance between live and processed food.

Fun fact about Oscars is they are called ‘river dog’ or ‘water dog’ because of their interaction with the owners. They even shake their tail and head regularly just as dogs do.

Also, they interestingly like redecorating their aquariums by moving things around and excavating the substrate. And are equally playful and intelligent enough to learn tricks like swimming through loops.


Like any other fish, an Oscars’ lifespan depends on the quality of care given to them. However, the average is quite impressive, with most living for 10 to 12 years.

To extend the lifespan of your Oscar fish, proper food and diet is a must. Also, keep them in a big tank since smaller tank stress and eventually harm them.

To be absolutely sure, go through an Oscar fish care sheet which gives detailed information on diet, breeding, and care tips before bringing one home.

Behavior and Temperament

Oscar fish are very so often territorial and will show aggression if other fish encroach their established areas. They prefer to enjoy their own space and are ideally not fit for community tanks.

However, they are not outrightly belligerent, especially not to their own kind, they are just big and will eat almost anything. To them, any small tankmate that fit in their mouth is fair game.

Oscar fish don’t get lonely or bored and can live happily in solitary.

If you are looking to turn your Oscar fish tank into a community, you’ll need to choose large passive fish that will keep away from your Oscars but also able to defend themselves.

The safest bet is to keep Oscars in a species tank if you have to raise them in a community. An ideal number would be four or five but never three Oscars. Because two fish out of the three can pair and gang up against a third fish.

Types of Oscar Fish

Overall there are three main types of Oscars, the Tiger Oscar, Red Oscar, and Albino Oscar. Any other variant that exists is either a crossbreed or dyed.

Dyeing is a process of changing the color of a fish unnaturally. Occasionally at pet shops, you will come across what is known as blueberry or strawberry Oscar. Or other exotic colors that cannot be created by live breeding, these Oscar fish are most probably dyed.

However, the dyeing process is cruel and highly discouraged. The process involves dipping the Oscar fish into a colored dye where the liquid absorbs to the fish skin which is obviously painful to fish.

Be it as it may, these are the 10 Oscars you are most likely to come across.

  1. Tiger Oscar: They have a dark base color with orange or red stripes. They are a result of selective breeding of red Oscar fish back to common Oscars.
  2. Red Oscar: Have a dark base color with a solid or mostly solid orange or red patterns that don’t form stripes. Red Oscars don’t have an eyespot on the tail.
  3. Albino Oscar: Mostly white with potentially vivid orange or red spots. The fish have pink eyes or possibly orange or red, and they have no dark coloration on the fins because that would make them lutino Oscars.
  4. Albino Tiger Oscar: They have a white or light base color with red or orange stripes.
  5. Albino Red Oscar: They have a white base color and solid red or orange patterns.
  6. Lutino Oscar: Bare a white base color with solid red or orange patterns and dark fins.
  7. Lemon Oscar: Have a brilliant lemon yellow coloring over an opaque, white body.
  8. Golden Oscar: They are similar to red Oscars but have more of a yellow golden color than red or orange.
  9. Super Red Oscar: They have an extremely vibrant solid red color.
  10. Veil Oscar: They come in all common color varieties but have longer than normal fins and tails.

Oscar Fish Tanks and Water Conditions

Oscars are fairly large freshwater fish, and it’s common for them to grow up to 18 inches long. So you will need an aquarium that can accommodate them comfortably.

The fish also produce some considerable waste from feeding and constant defecation around the aquarium. The large bioload is as a result of their large appetites and carnivorous diet, for this reason, you’ll need a high-quality filtration system.

Since Oscar fish come from warm tropical climates they need to be in warm aquarium water.

Here are complete tank and water condition guides.

Tank Condition

As mentioned before, Oscars need a fairly large aquarium, at least 55 gallons or more. Smaller tanks limit mobility for the fish and sometimes get too small and stressful for their fairly large size.

Ideally, each fish would need about 20 to 30 gallons given their territorial traits and considerably high aggression. For maximum comfort, a large 125 to 150 gallons tank is feasible even for just two Oscar fish.

When raised in aquascaped tanks, Oscar fish regularly lift out the plants and even move rock around the aquarium. Therefore consider adding artificial instead of living plants.

Alternatively, use hardy or floating plants like hornwort which are safe from damage or can at least survive the trauma.

At the bottom of the tank, though gravel is frequently used, a course substrate risk bruising Oscars when they dig. So, layer your aquarium with a soft substrate like fine-grained sand.

Also place rocks and bogwood around the tank for your Oscar fish to play with. It also should, however, not surprise you if lighter rocks are constantly in different positions since Oscars are known to redecorate.

To help you clean the terrible mess the fish make, use a high-quality filtration system.However, before you set it up, ensure the system can at least remove food particles from the water. And also control chemical and biological agents, reduce ammonia and oxygenate the water. Then keep the filter running at all times.

To keep the water safe even with the filter running, replace about ten percent of the tank capacity on weekly.

Two other things to consider are lights and a lid for your aquarium. Because Oscars jump out sometimes even to their death, It’s best if the lid fits securely over the top of your tank.

Still to discourage the fish from jumping, keep the underside of your tank lid clean to stop dirt from falling off the lid and causing ripples. Fish will jump if they confuse the ripples with those made by a ready meal as they would in the wild.

Water Conditions

Since Oscar cichlids are native to South America, so try to replicate the conditions of the tropical wild waters.

Generally, Oscars like warm water which is anywhere between 74°F to 81°F. If your tank is too cold, consider purchasing an aquarium heater.

About water quality, the fish are not fastidious. However, they still require alkaline water with a pH range between 6.0 and 8.0.

However, once you’ve properly acclimated your fish the first time and they are comfy, you’ll only need to maintain the water in those conditions. Though it could be tedious when you change the water which for Oscars is quite frequent.

A quick and helpful chop is to change your aquarium water partially. This way you’ll always have half the tank’s water in the appropriate conditions thus barely shock your fish.

Keep tabs of your water temperature with a thermometer and use an aquarium pH test kit to mete the water. Also, use cichlid buffer or a water conditioner to constantly keep the aquarium water ideal.

Oscar Fish Tankmates

Although Oscar fish prefer to live on their own, it’s not entirely impossible to put them in a community tank. It does, however, depend on your fish demeanor and attitude. So, it’s fair to consider this a classic hit and miss situation.

As a rule, don’t house Oscars with fish that can fit in their mouth otherwise they’ll be turned into a quick snack. Also, as mentioned before, consider bigger but subtle fish that will not bother your Oscar fish but will defend themselves where need be. Better still, raise them in a species tank.

Another rule of thumb is to make sure you have an appropriate tank for big fish, some of whom may or may not be aggressive.

That said, see the list of fish I’ve had reasonable success with or at least know aquarists who have.

  1. Jack Dempseys: If housed together, a 55-gallon tank will only just cut it, and many would say it’s not large enough, that a 90 gallon is needed.
  2. Plecos: If you want to keep Plecos successfully with Oscar fish, you will need the pleco to be at least 8 inches. Otherwise, your pleco will soon turn into a meal.
  3. Fire mouth Cichlids: These are probably the only small-sized fish that dares to confront Oscars. The Firemouth behavior is more in the line of the Convicts, showing no fear but having no problem to retreat and if possible avoid the bigger fish.
  4. Convict Cichlids: These two definitely go well together, as long as the Convicts are not too small that they fit in the Oscars’ mouth.
  5. Arowanas: Both of these are pretty big and messy fish so you’ll need to be careful not to max out your tank.
  6. Jaguar Cichlids: If you house them together, make sure you have a big tank. Better if it’s planted to avoid confrontation, otherwise this could turn into a scandalous crapshoot.
  7. Senegal Bichirs: Oscars and Bichirs live well together as long as the bichir is big enough that it won’t get eaten.
  8. Green Terrors: This matchup does not always work, a lot will depend on the attitude and aggression levels of your GT. They aren’t called “Green Terrors” for nothing! All you can do is try it, and have a backup plan if it fails.
  9. Silver Dollars: Silver Dollars make fantastic tankmates for Oscars. The only catch is Silver Dollars schooling fish hence prefer being in a group.

Food, Diet and Feeding Oscar Fish


Oscar fish feed on a wide variety of food. In fact, they taste anything consumable in the aquarium, including smaller fish.

In the wild, they, however, eat a variety of insects and crustaceans same way they do live foods in the fish tank. But not all live foods are good for Oscar fish, an appropriate size that will fit in their mouths is crucial.

Moreover, while feeding live foods increase growth rate, it also causes diseases like endoparasites. And don’t feed your fish mammalian flesh as they cause fatty liver disease.

Recommended live food for Oscar fish include:

If are you have difficulties getting healthy live foods for your Oscars, consider breeding your own. Guppies are prolific breeders and are often used as feeders. Rosy red minnows are a good alternative when you don’t have guppies.

Feeder goldfish are not ideal for Oscar’s because they are typically kept in overcrowded tanks and are prone to diseases. If you must feed goldfish, be very selective and never purchase from a tank with sick fish.

The other option is to buy commercial foods like pellets.

When shopping, look for food designed for cichlids with superior dietary content.

Conviniently, a large selection of pellet foods is available, as well as frozen, freeze-dried and canned foods.

Recommeded commercial food for Oscar cichlids include:

Recommended commercial food for general cichlids


Feeding Oscars is not tasking when you know the right food for them, but it is important to use the highest quality food available.

Combine a mix of live and commercial food to give your fish an all rounded diet. Plus don’t be afraid to feed them fruits and peas because Oscar fish are omnivores by design.

Feeding Oscars with peas is believed to help improve the color and vigor of the fish, plus green peas are used to cure constipation. Fruits and nuts in the diet also help meet Oscar fish high requirement of vitamin C.

However, be wary of dried foods because they contribute to blockage, bloat, constipation and could result in the death of your fish. Also, when feeding your fish with fruits and vegetable, ensure all seeds are removed to reduce the blockage risk.

By and large, marble cichlids diet should be mostly meaty foods since that’s what naturally bonds with their wild diet.

A good way to assess whether the diet you are feeding your fish is balanced is observing their eating habits. A lot of wasted food could, among other things, indicate a meal that is not particularly appealing. Also, an active and healthy looking fish is definitely well fed.

Feed Oscar fish a couple of times a day, in amounts they can finish in a couple of minutes. But watch out for aggression as these cichlids get excited around food.

Eventually, remove any uneaten foods after a while before they start deteriorating your aquarium water.

Breeding Oscar Fish

Apart from finding appropriate tankmates, the only other thing hard enough is breeding Oscar fish.

Generally, they reach maturity at approximately one year but may refuse to spawn until they are two to three years old. Moreover, Oscar fish are monomorphic meaning the male and female fish look exactly the same. Which conveniently make it an uphill task to tell them apart.

Sexing and Breeding Signs

To sex your Oscar fish, look at differences in the shape of genital papillae located somewhat close to their anal opening.

Basically, flip your fish over enough to see the genitals, then observe the size, shape, and color of each, in females, one hole should be bigger, but in males, the two holes are the same size.

The big, blunt, and wide-mouthed hole is the egg tube.

Also, males have been said to grow faster and have dark blotches at the base of the dorsal fin. Meaning a female’s skin will be lighter than the male’s skin around the genitals.

Unfortunately, the challenge doesn’t end at sexing. Assuming you identify the sex of your Oscar properly, spawning is temperature dependent and may be restricted to warmer spaces.

Another catch is the signs they exhibit when ready to reproduce. Normally, aquarists know Oscar fish to be quarrelsome hence most will miss signs of elevated aggression in mature Oscar fish ready to breed.

So, should you miss that, at least catch one of these other signs:

Spawning Conditions

Once your Oscar fish show signs they are ready to reproduce, you’ll need to provide proper conditions for them to breed.

A 55 gallons aquarium is considered minimal for a pair of six-inch fish but 70, 90 or 125 gallons aquariums are better.

Next, make sure your aquarium filtration system will accommodate the enormous waste produced by Oscar fish. According to Pet Central start with a double outlet, powerhead-driven underground filter weighted with heavy rocks beneath one inch layer of gravel.

You’ll also need a large canister filter with ammonia removing zeolite and a hang-on-the-back filter with fiber foam and activated carbon.

Then use large rocks, clay flowerpots or large diameter PVC pipe to provide refuge either for the male or female as Oscar fish become aggressive before and after spawning.

Also, since in the wild Oscar fish breed in the rainy season, lower your aquarium temperature a couple of degrees to mimic rain. Water changes every couple of days plus sprinkling water on the tank surface should help as well.

When the fish are ready to spawn, they’ll clean a rock surface to lay their eggs on. Which means you need to make sure there is a wide flat rock or piece of slate about eight to 12 inches in diameter in the aquarium.

Normally after the female lay her eggs, both parents will guard them till they hatch after two to three days.

Once you have newborns, move them to another tank with a sponge filter and continue taking care of them.

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Have fun with your lady betta.

Enjoy being an Oscar fish owner!

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