The Oscar Fish Care Guide: Types, Tank Setup, Diet, and Breeding, etc.

Oscar fishes are beautiful with vivid patterns and, when it swims, looks elegant. Anyone can be easily deceived from their intimidating appearance. But before you plan to buy a freshwater oscar fish for your aquarium, it is important to know everything about them.

Oscar (fish) hides aggression under their colorful skin. They are quite active and intelligent. It can become quite challenging for beginners to keep them. So, it is advised only the aquarist who has kept other aggressive fishes before should only keep Oscars.

They are not ideal for keeping in the community tank. Oscar cichlid can attack or fight with other fishes and can hurt themselves or others. They are omnivores, so they are easy to feed, and a variety of food can be added to their diet.

To know more about them, keep reading till the end.

Category Rating
Family Cichlidae
Diet Omnivorous
Temperament Aggressive/Territorial
Care Level Moderate
Size Up to 12 inches (18 inches sometimes)
Color Form Various
Lifespan Up to 20 Years
Compatibility Large, Passive Fish
Tank Set-Up Freshwater, Rocks, and Caves
Minimum Tank Size 55 gallons


Oscar Fish Overview

Tiger and red oscar fish

Oscars, from the family Cichlidae, are also known by the name Astronotus Ocellatus and Astronotus Tigris.

The majority of them are native to South America, just like other members of its family.

They are easily found in the Amazon river or rivers of other Tropical countries like Columbia, French Guiana, Brazil, Peru, and Brazil. They can be kept in a home aquarium, and the aquarists around the globe, especially from North America and China, are known to keep them.

The Oscars are infamous for their aggression but famous for their vivid appearance and color. They are also found in many patterns. They can become quite territorial and harm any fish that comes near them.

How Long Do Oscar Fish Live?

Oscar fish lifespan is nearly 20 years if kept in a healthy environment and fed well. You can buy Oscar (fish) from any pet store, and a healthy Oscar cichlid can be bought at $10.

Oscar Fish Behavior

The Oscars dwell in the mid-level of the tank but are quite territorial. They will destroy anything that comes in their way. They can also be seen spending time in the bottom, uprooting plants and decorations, or searching the food. The personality of oscar cichlids is different from other fishes.

Their aggression can be seen at peak during the mating season, while feeding, and also if the tank is overcrowded. It can be controlled by choosing the right mates for them and keeping the number of fishes as low as possible.

Types of Oscar Fish

The Oscar fish can become large, and most of the species can reach up to 12 inches. It quickly becomes fully mature, the oscar fish growth rate is one inch per month, comparing its long lifespan.

Their long oval body is usually found covered in vivid patterns with bright or bold coloration. Their fins have a fan-like look with dorsal and anal fin extending along the body.

Tiger oscar fish
Tiger oscar fish and red oscar fish

The male and females look alike and only be distinguished by taking a closer look at their genitals. It makes them monomorphic.

The experts have created many varieties of Oscars by breeding them in captivity. The original Oscars have irregular black and orange splotches over their body. They are also recognized as Tiger Oscar fish, but the color may change with time.

The Oscars are now found in other different colors as well. The species with solid red or yellow colorations are called Red Oscar fish and Lemon Oscar fish, respectively. They are found to have either black or white fins that add charm to their appearance.

Lemon oscar fish

Another famous choice among Oscar lovers is Albino Oscar fish that has bold white color all over their body.

Oscar Tank Setup

For keeping any fish happy and thriving, it’s important to replicate the water conditions to their natural habitat. They are found in rivers like the Amazon, where the flow of water is strong. So, you have to set up an oscar fish tank accordingly.

A freshwater oscar tank setup

Take a brief look at the table to understand the tank requirements for your Oscar –

Conditions Parameter
temperature 74-81°F
pH 6-8 pH
water 5-20 KH

The given conditions are easy to create and maintain in the tank. The water in the tank should be warm, which can be maintained through the heater and checked through the thermometer. A filter will keep the water clean and will also help in creating waves for them in the tank.

For the bottom, choose a soft substrate like sand instead of the one with granules. The soft substrate will avoid Oscar from getting scratched while searching or digging for food.

You can place any plant or decorations of your choice. Add caves for each Oscar (fish) so that they can hide whenever they feel threatened. To make the environment of the tank look natural, you can also add rocks and bogwood around the tank.

Whatever you put or fix in the tank, make sure they are firmly attached. Oscars are known for digging everything they can. Oscars can uproot the plants and decorations, and you will have to locate them again and again. Hornwort is a floating plant that will be able to take the nipping from the fish. You won’t need to put a lot of effort into maintaining them.

The substrate should be sand to keep Oscar (fish) from getting hurt while digging. If the substrate is granules based, they can end up scattering them everywhere. They are not only aggressive but also an active swimmer. They are also powerful enough to jump out of water or make others jump. So, make sure the lids of the tank are also closed or fixed firmly.

Oscar Fish Tank Size

Oscars are large and territorial, so that you will need an aquarium with a larger tank capacity. The small tank won’t let them swim freely and can cause stress in them instead. This stress can make them aggressive and ill.

How Many Gallons Does One Full-size Oscar Need?

For starter, 55 gallons is enough for keeping a single Oscar cichlid and add 20-30 gallons per Oscar fish you add in the tank. Each Oscar will need their territory and space to swim. Otherwise, they will start fighting over territory.

Oscar Tank Mates

Albino oscar fish
Albino oscar fish

Selecting an Oscar tank mate is not easy. The Oscar fish is not good at making friends or being social. It could attack the other fish if they entered in Oscar’s territory. If the fish is small, Oscar cichlid will turn it in their dinner. In their natural habitat, Oscars can be found living with other fishes. You should know which fish compatible with Oscars.

Still, keeping Oscars in a community tank isn’t a good idea. But if you are too determined to make a community tank, make sure to add only the species that are compatible with them and won’t cause any trouble.

Fishes that are big like Oscars and have passive temperament can become a great companion. They won’t come in their way, and if they did, they would be able to defend themselves.

What Fish Can Live with Oscars?

Some popular freshwater fishes that can become their companion include – Convict Cichlids, Severum Cichlids, Arowanas, Silver Dollars, Jack Dempseys, Bichirs, Sailfin Plecos, Firemouth Cichlids, Jaguar Cichlids, and Green Terrors. Don’t put any small creature, like small fish, snails, or shrimp in the tank. They will quickly turn into the food for Oscars.

You can put Oscars in a group also, but only if there is ample space for swimming and marking it as their territory. The environment also determines the level of aggression in the Oscars.

Oscar Feeding and Diet

Let’s discuss the oscar fish diet. Oscar is omnivores like other members of its family. Providing them with healthy food is not that difficult, and they will eat whatever you feed them. Small fish, crustaceans, plant debris, larvae, and insects make up the large part of their diet in their natural habitat.

What Do Oscars Eat?

Beginners always wanna know, what can I feed my oscar cichlid. In an aquarium, you can feed them with premade to homemade and vegetables to meat. You can feed them vegetables by chopping them in small pieces or mashing frozen peas. For meat, you can put brine shrimp, bloodworms, and daphnia into the water. Oscars will happily hunt them and eat. Add live food only when they are more than 4 inches.

Apart from that, include high-quality flakes and pellets in their diet. They are rich in nutrition that will help in the development of your Oscar. Some food, specifically made for Cichlids, is also available in the market.

Oscars are gastronomes; they won’t mind eating the whole day. They can get competitive and aggressive while eating. But it can lead to overeating, which is not healthy for any fish.

When Oscars are young (less than 4 inches), you can feed them thrice a day and only the amount they can finish in 3 minutes. For Oscars, more than 4 inches and adults, you can be fed twice a day. You can limit the feeding to once in 4 days to once in a week for adults. It gives time to process the food properly.

Also, make sure to put another piece of food only when they have swallowed the first one completely. They are competitive, so they will simply spit the food without finishing it to catch other food dumped in the tank. Make sure to add variety to the food. It will provide a wide range of nutrition. Oscar fish grows quickly, and they thrive only when they are fed properly.

Oscar Fish Care

Oscar fish care
Astronotus Tigris

Oscar (fish) needs more care than any other fish. It is important to provide them with a wide range of nutrition in their diet. The deficiency of nutrition or overfeeding can lead to many diseases in them.

Also, changing the water once or twice a week is important. It will maintain the water conditions and help in reducing the toxin level in the tank. The one common disease found in the members of the family Cichlids is ‘hole in the head’ disease.

Disease Hole in the Head
Caused by Parasite ‘Hexamita’
Symptoms Lesion on head or body, loss of appetite, faded coloration, white stringy feces
Found in Large Cichlids like Oscars and Discus
Cure Add antibiotics to the tank and nutrition-rich foods like broccoli, etc.

Oscar Fish Breeding Guide

Oscar is another breed of fishes who are hard to breed. You can’t just put pair of male and female Oscars in the tank and expect them to mate. They won’t mate unless they find their suitable partner.

You have two options to make sure they breed. First, you can buy an already mating pair. Second, you can buy a group of young Oscars and wait till they grow up and find their suitable partners. The second process can take 1-2 years, while the first one won’t take much time.

The rainy season is the perfect time for Oscars to mate. In an artificial tank, you can make the mating environment by lowering the water temperature to a few degrees and sprinkling water on the surface for a few minutes.

The spawning fish will indicate her partner by flaring gills and waggling their fin. The pair will then clean the rock surface for eggs. A healthy and large Oscar female can give birth to up to 3000 eggs.

After the eggs are laid, the parents guard it. The female will fan them while the male will keep other fishes away from the eggs. It can take 2-3 days for the eggs to hatch. You can also move the eggs to another tank with a sponge filter. It will increase the chances of survival for the fries.

The fries need constant care and can be fed in a small amount for 3-4 times a day. It will trigger their growth. But you can put a group of Oscars in a small tank. It will cause stress and can hinder their growth as well.

Should You Keep Oscar Fish?

Oscars are hardy, but keeping them in already set up an aquarium is not a good idea. It is advised to set up a tank by keeping the requirements of Oscar in mind.

Once the tank is set and running, you won’t face any big challenges with them. Oscars will add vividness and variety to your tank. Their activities will keep you engaged with them, and they will soon become your favorite.

You can face a challenge while preparing for breeding them, but you will get a chance to experiment with their diet. You can add variety to the diet that will help in maintaining the nutrition level.

Do you own an Oscar fish or planning to have one? And do you keep them in pairs or single? Let us know in the comments.