Oscar Fish Stats InfographicOscar Fish, also known as Tiger Oscar, Velvet Cichlid, or Marble Cichlid, make wonderful pets for the experienced aquarist. These intelligent fish form a bond with their owners.

Tiger Oscars are very popular in the fish hobbyist community because of their striking coloring and long life span. Their unusual behavior will keep you captivated for hours.

This guide will help you understand how to provide the best care for the Oscar Freshwater Fish. You will find details about the proper diet, tank size, water parameters, and suitable tank mates for this amazing fish.

Oscar Fish Stats

Scientific Name Astronotus ocellatus
Common Name(s) Oscar Fish, Oscar Cichlid, Tiger Oscar, Marbled Cichlid, Velvet Cichlid, Water Dog
Family Cichlidae 
Origin South America
Care Level Moderate
Temperament Aggressive/territorial
Lifespan Up to 20 years
Size Up to 12 inches
Diet Omnivore (pellet food, freeze-dried shrimp, live worms, peas, etc.)
Tank Size 55 gallons or more
Tank Set-Up Freshwater, with hiding places
Compatibility Large, passive fish
Temperature 74 to 80 F
pH 6 – 8
Tank Mates Firemouth, Jack Dempsey, Common pleco and Clown loaches

– Habitat and Origins

Oscar Cichlid is a species of cichlid from South America, where they find the appropriate habitat for their survival all along the Amazon River basin. It is possible to find this fish in several countries, including Colombia, Brazil, Venezuela, Ecuador, and more.

The slow-moving white waters have lots of rocks, submerged branches, foliage, and debris that are the perfect spots for these fish to hide from predators.

– Oscar Fish Appearance

Oscar fish food requirementsOscar Fish is a large, chunky fish with a long, oval body. Its head is large with big eyes and a wide mouth. Their caudal fins are symmetrical, as it normally happens with cichlids. Their dorsal fins and anal stretch as far as their caudal fins, making them look quite stocky.

It is impossible to differentiate between male and female Oscar Fish as they look alike, and there are no distinguishing features.

Juvenile Oscar Fish has wavy white and orange bands and small white spots on their heads. Adult Oscars are also called Marbled Cichlid because they have speckled orange and reddish patterns on an olive-green, gray, or chocolate brown body. These fish typically have a large black spot with a vivid orange ring on either side of their upper caudal peduncle.

– Oscar Fish Size

Among aquarium fishes, the Oscar Fish’s growth rate really stands out. The juvenile Oscars sold at pet stores are about 1 to 2 inches long. However, they grow 1 inch a month and can be 8 inches long by the time they are a year old.

Oscar Fish grow approximately 10 to 12 inches long in captivity, although they can be 14 to 16 inches long in their natural habitat. Since this beautiful fish is so large, you must ensure your Oscars have a spacious tank with sufficient space to be comfortable.

– Oscar Fish Lifespan

The Oscar Fish lifespan is between 10 and 13 years. However, they can live up to 20 years if you keep them in the right environment and take good care of them. If you have an Oscar Fish, you can enjoy having your pet with you for many years.

The South American Oscar Fish live much longer than other similar fish like the African Oscar Fish.

– Oscar Fish Behavior

Oscar Fish Behavior is unusual. They are an intelligent species that bonds with their owner. They are sometimes called “water dogs” because of the way they come forward when they see you and shake their head or tail fin, just as dogs wag their tails. They may even beg for food.

Oscar fish have a reputation for being aggressive, which is not quite true. They can potentially be hostile or territorial if they are in a crowded tank or with unsuitable tank mates. But if you’ve researched thoroughly and created an environment where they are comfortable, your Oscar Fish can be quite good-natured.

Once these fish settle into an aquarium, they like to swim around and explore the surroundings. Be careful: while they do so, they can potentially overturn rocks and other decorations in the aquarium. They may even uproot plants as they dig through the substrate if they’re hunting for food.

Oscar Fish Care

To provide Oscar Fish care means understanding the basics and providing them with the best possible environment that suits their preferences. Your Oscar Fish will be happiest if you set up your aquarium to mimic their natural habitat: warm with a neutral pH, like the waters of South America. They are also used to a strong flow since they primarily live in the Amazon River.

Oscar Fish are extremely sensitive to changes in water chemistry, so they can’t tolerate extreme ranges in acidity or alkalinity. These fish are also very sensitive to ammonia and nitrite, so you must cycle your tank before bringing your Oscar Fish home.

– Water Parameters

Oscar Fish is indigenous to the Amazon river, where temperatures are from 76 – 78 F. If you keep the temperature in your tank too low, Oscars can be prone to infection and disease. However, excessively high temperatures can lead to reduced oxygen levels, which is also harmful.

Hence, only if you maintain the water parameters in your aquarium within the recommended ranges, will you be able to ensure the well-being of your fish.

Water temperature 74 – 80 F
pH levels 6 – 8
Water hardness 12 – 15 dH

Another thing you will need is to install a quality aquarium filtration system. Remember that the large Oscar Fish eats a lot of food. Therefore, it also produces a large amount of waste. Since these fish are sensitive to ammonia, we suggest a canister filter and a hang-on back filter.

Finally, it is necessary to make a regular schedule to test the water since major changes to water conditions can result in serious health concerns for your Oscar Fish. It would help if you carried out water changes of 20 percent every two weeks.

– Oscar Fish Tank Size

The first step towards good care for your Oscar Fish is the tank. The size of your aquarium is an important factor, as a full grown Oscar Fish requires a minimum tank size of 55 gallons. If you’re planning to keep more than one Oscar fish, then 80 to 100 gallons would be better, and 125 gallons would be ideal.

Many new hobbyists are unaware that the 2-inch-long juvenile fish they bought can grow an inch a month and will soon outgrow a small tank. This becomes a problem since they are not prepared for a fish that is 12-inches long.

You must also consider the shape of the tank, as that is as important as the size. The ideal would be a wide tank in which your Oscar Fish won’t bump into the walls while swimming.

– Oscar Fish Tank Setup

The Oscar Fish’s aquarium setup impacts their stress levels, so it is essential to provide an environment where your fish are happy and comfortable. Decorating an aquarium for Oscar Fish can be challenging, as these large fish are strong enough to push over small objects easily and uproot plants. However, you still want to carefully prepare your tank setup.

Oscar Fish like to dig around and hunt through the substrate, so you should have a soft substrate like sand or fine gravel, so they don’t get cut by sharp edges of rocks or coarse gravel. It is advisable to avoid using coral, limestone, or any other calcium carbonate-based minerals that can change the pH levels. These species are soft-water fish, and they don’t tolerate these changes.

Hiding places, where your Oscar Fish can feel protected, are also a must. Driftwood, logs, and rocks serve as suitable hiding spots. Large rocks and bogwood, in particular, are appropriate for creating small caves that each specimen can claim as their own.

You can also add floating plants, like Hornwort. They are sturdy plants and won’t be damaged by the Oscar Fish. Don’t forget to firmly fix the decorations and keep them at a minimum to leave ample swimming space. Oscar Fish prefers moderate to subdued aquarium lighting. Some LED lighting will make their colors stand out, but you must turn the lights off every eight to 10 hours to prevent the fish from getting agitated or set the lights on a day-night cycle.

– Oscar Fish Diet

Oscar fish water requirementsThe Oscar Fish diet should include a variety of food that provides the nutrients your fish requires. These fish are omnivores and they would eat small fish, larvae, insects, crustaceans, and other invertebrates in their natural habitat.

Oscar Fish will also eat other fish since they can swim quickly for short distances. However, live fish are not normally a part of their diet. They may also feed on fruits, plants, and seeds available in the waters around them.

There are many options available when it comes to the best food for your Oscar Fish since they are not picky eaters. The easiest way to make sure that your fish are properly fed is to use quality cichlid or Oscar pellet food, designed specifically for this kind of fish. In addition, you can supplement pellet food with protein-rich freeze-dried, fresh, and live foods.

Here is a list of suitable food for these fish:

  • Freeze-dried shrimp
  • Fresh shrimp
  • Fresh scallops
  • Fresh clams
  • Live snails
  • Live earthworms
  • Live mealworms
  • Bloodworms
  • Brine shrimp
  • Daphnia
  • Peas
  • Bananas

We suggest feeding your fish twice a day, in amounts that they can finish in a couple of minutes. We would not recommend live-feeder fish like Goldfish and Rosy Red minnows since they have very little nutritional value. Feeder fish can also introduce parasites and bacteria into the aquarium and cause several diseases.

– Oscar Fish Tank Mates

Oscar Fish Tank Mates need to be carefully chosen since there is a possibility for aggression or hostility. In terms of Oscar Fish compatibility, the most suitable are other Oscar fish, as long as you ensure the minimum tank size requirements.

Oscar Fish can be territorial. They may try to protect their territory from other fish in an aquarium just as they do in their natural habitat. Additionally, Oscar Fish tends to feed on other small fishes if they are available. Goldfish or guppies will make a tasty snack if you add them to an Oscar Fish’s tank. The same holds for small invertebrates like snails and cherry shrimps.

While Oscar Fish may be hostile towards other fish, they can be bullied or attacked by larger or more aggressive fish. If you wish to keep your Oscar Fish in a community tank with other species, you must be careful to pick fish that are large enough to cope with the Oscar Fish but won’t bully them either. Some fish to avoid are Flowerhorn cichlids, Jack Dempseys, and almost all large African cichlids.

Some compatible Oscar Fish tank mates include:

As you can see, there are so many compatible tank mates you can choose from, and most of them are other cichlids. They can be spunky, but they are not aggressive, so they can live together peacefully with your Oscar Fish.

Many of these fish are big, so if you intend to add them to a tank with your Oscars, it is vital to make sure the tank is spacious enough for all the fish to live comfortably. You must also make sure your filtration system is sufficient to handle the increased bioload of all these fish.

Oscar Fish Breeding

Oscar Fish breeding requires a lot of effort and patience, as these are some of the most challenging fish to breed in an aquarium. However, the result is well worth the hard work.

To begin with, make sure you have a suitable breeding pair of adult Oscar Fish. These fish are very particular when picking a mate, so putting a male and female together will not necessarily result in their bonding. Also, you cannot tell the difference between them since the male and female fish look the same.

One option is to buy Oscar Fish that has already formed a pair. Another possibility is to buy a group of juveniles, who will naturally form mating pairs as they grow up together. If you wish to raise your breeding pair, you must remember that Oscar Fish takes about two years to become mature enough to breed.

– Creating the Perfect Environment

In the wild, Oscars breed during the rainy season. However, you may need to help your fish since they live in a tank. When you’re ready for the fish to spawn, you can encourage them by changing 20 – 30 percent of the water. Changing more water than usual tells the Oscar Fish that the breeding season is approaching. You could do this during your regular weekly water change to avoid stressing the fish.

Temperatures generally drop, and the weather becomes cooler during the rainy season. Lower the temperature in the tank by 3 to 4 F. Don’t lower the temperature too much because it could shock your fish.

The next step to stimulate the Oscar Fish to spawn is by mimicking rainfall. You can spend 10 minutes a day sprinkling water on top of the tank.

Condition the breeding pair by Oscar by feeding them live food such as frogs, crayfish, freshwater shrimp, and minnows. Now you can start to watch for breeding rituals. Sometimes, Oscar Fish breeding rituals can appear pretty aggressive. You may see your fish chasing each other around the tank, slapping tails, or locking mouths with one another.

– The Egg-Laying Stage

At this time, you should provide them with a large flat rock for the female to lay her eggs. Female Oscar Fish will not lay their eggs on the substrate. After the Oscar Fish clean the rock, the female will lay her eggs, and the male will fertilize them. Oscars are extremely protective of their area while spawning and will not allow any other fish to come near it.

The eggs will take three to five days to hatch. You will see what looks like a wriggling mass with tails stuck to the slate. This is the fry as they start to get nutrition from their yolk sacs. Once the fry finishes their yolk sacs in about four days, they will begin swimming independently and start to eat baby brine shrimp.

Oscars are good parents who will care for their eggs and fry, so you should leave the fry with their parents for about a month before you move them to another tank.

– Setting Up a Fry Nursery

If you wish to remove the Oscar fry to a separate tank right away, we suggest you prepare it as soon as you see the eggs because they will hatch in three days. Fill the tank with water from the parent tank to prevent shock when you move the fry.

You may see the parents eating some of the eggs. This is quite normal as they do this to remove deformed or unhealthy eggs from the batch. You may see the eggs shaking slightly when they are about to hatch as the fry try to break the shell.

Gently scoop the fry up with a container. Be sure you avoid exposing them to air while you move them to their own tank.

– Feeding the Baby Oscars

Although Oscars are omnivores, juvenile Oscars require some protein for a balanced diet. High protein flake and pellet fish food make for a rich and nutrient menu. You could also supplement their diet with fresh and live fish food. White worms are an excellent addition to their diet because of their high protein and fat content.

We suggest feeding the fry three times a day with live, frozen, or freeze-dried blood worms, brine shrimp, tubifex worms, black worms, and small shreds of frozen krill until they are one month. Once the Oscars are older, you should offer them shrimp, Cichlid pellets, earthworms, frozen krill, live crickets, lettuce, peas, cooked or fresh fish, and minnows twice a day.

Feeding patterns and timings also affect the growth rate of these fish. We suggest feeding the juvenile Oscars two or three times a day instead of giving them one large meal daily. It is also advisable to feed them a variety of food to ensure a balanced, nutritious diet. You should offer them different types of food each time as a good way to vary their diet.

– How To Feed Juvenile Oscars

Once the juveniles reach 4 to 6 inches in length, you can change the frequency of the feedings. Feed them once or twice a day. The juvenile Oscar Fish should be more settled by now, and feeding should become easier.

At 7 or 8 inches, Oscar Fish are considered adults. It is advisable to watch the weight gain of these fish as they are growing. If they are gaining too much weight, you should adjust their diet, the food type, and the frequency accordingly. It is sufficient to feed adult Oscar Fish once a day or even every other day.


How to take care of oscar fishOscar Fish make wonderful pets as these fish are very intelligent and will bond with you.

  • Oscar Fish is one of the fastest-growing aquarium fishes
  • These fish grow one inch a month
  • Oscar Fish can live more than 13 years with good care
  • An adult fish can be fed once a day or once every other day
  • These fish are good parents
  • Oscar Fish are omnivores
  • They are not picky eaters

If you are looking for a beautiful, big fish that can be a long-term companion, you should certainly get an Oscar Fish.

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