Fish Species Profile, Oscar

Oscar cichlid

The common Oscar fish may be distinguished by its distinctive black and orange stripes. This species, which belongs to the Cichlidae family, has mutations that result in bright colors like yellow and blue, largely black, and even all-white appearances (albino).

What is an Oscar Fish?

The Oscar fish are a tropical species that are indigenous to South America. They are sometimes called the Tiger Oscar, Marble Cichlid, or Velvet Cichlid. Oscar fish in a variety of colors are popular in freshwater aquariums, however owing to the Oscar's territorial tendency, tank mates must be compatible with its temperament.

These fish are distinctive for their personality as well as their appearance, which makes them simple to spot: Oscars agitate objects inside the aquarium and are aggressive against other fish that share their home.

Species Overview

Common Name(s): Oscar, Tiger Oscar, Marble Cichlid, Velvet Cichlid

Scientific Name: Astronotus ocellatus

Adult Size: 12 to 14 inches

Life Expectancy: 10 to 15 years

Family Cichlidae
Origin South America
Social Semi-aggressive
Tank Level Top, mid-dweller
Minimum Tank Size 65 gallons
Diet Carnivore
Breeding Egg layer
Care Advanced
pH 6.0 to 7.5
Hardness 5 dgH
Temperature 72 to 77 F (22 to 25 C)

Origin and Distribution

Like many South American cichlids, the Oscar originates from the Amazon and Orinoco river basins. They are common in the aquarium hobby with most individuals being captive bred.

They have been imported to Asia, Australia, and North America and are frequently marketed in South American markets as food fish. Where fish have been introduced into the wild in the US, they are classified as a non-native nuisance species.

Colors and Markings

The common Oscar, commonly called the "Tiger Oscar," is a fish with deeper brown to light green body color with red and orange accents. There is a distinctive eye spot, or ocelli, on the tail fin that gives the color pattern a wide range of variation. There are albino variants that have a body that is entirely white with red markings.


When choosing tankmates for your Oscar, exercise extreme caution. Despite their initial size, many rapidly outgrow their smaller tankmates and devour them. These cichlids are moderately aggressive and do not get along with most communal fish. Make sure to choose fish from the same location when picking appropriate cichlid species. Cichlids come in a wide variety of kinds, but the optimal water quality characteristics will depend on where they came from. Be sure to stick to other South American kinds because oscars are South American.

It is advisable to choose fish for your Oscar tank that are comparable in size and capable of competing. As a few instances, think of Jack Dempseys, Convict Cichlids, and Silver Dollars.

Oscar Habitat and Care

The Oscars are infamous for redecorating. Don't expect your fish to move anything if you become attracted to anything in the tank. This is especially accurate for living, rooted plants. Oscars will destroy plants, flip over rocks, and throw away wood. They simply do it naturally, and there isn't much you can do to stop them.

This hostile behavior against their tank decorations might develop into aggression toward the heaters, powerheads, and other life-supporting equipment you have in their tank. Even if you try to hide these things cunningly, Oscars have been known to smash things. Including a sump is the greatest remedy for many harmful Oscar tanks. By doing this, you can remove all of your life-support systems from the main tank and keep them out of the fish's reach.

Oscars are picky about proper water chemistry, thus it's critical that you maintain your routine maintenance and frequently test your water chemistry. Fish that are consistently stressed are more prone to developing Head and Lateral Line Erosion, often known as Hole-In-The-Head illness.

Oscar Diet and Feeding

Oscars are serious carnivores who will prey upon smaller, more docile fish in their tank. It is critical to select suitable tankmates who will not look or act too tasty.

A balanced diet for cichlids will include a pelleted cichlid food and meaty supplements, as it does for the majority of pet fish species. Many pelleted cichlid diets, including those for carnivores, are suitable for a range of cichlid diets. Give your Oscar bloodworms, tubifex worms, frozen krill, and other bigger frozen as additional protein-rich meals. Although some advise giving your Oscar live meals, you should avoid doing so to prevent the spread of disease and maybe overcrowding your tank.

Gender Differences

Male and female Oscars differ just little on the outside. You must catch and handle your fish carefully, then turn them over to look at their urogenital openings. The entrance for the eggs will be in one bigger hole in Oscar females. Oscar men will have similar-sized holes. No matter what the gender, the holes will appear to be the same size if they are not reproductively mature.

Breeding the Oscar

They might not be interested in mating even if you just have one male and one female Oscar. Oscars have a reputation for being choosy when choosing a partner. Do not give up if your fish do not show any interest right away. Instead, consider relocating them to their primary tank, adding new decorations to the breeding tank, or purchasing a larger breeding tank.

It is advised to breed your Oscars in a tank that is isolated from other fish and at least 100 gallons in size. In order to encourage spawning, the temperature must be higher than in their normal tank, between 79 to 86 F. (26 to 30 C). The fish will require a rough ground to deposit their eggs on. The male will swim over to the female's 1,000–2,000 eggs and fertilize them. The parents will watch over the eggs and fry, which should stay in the breeding tank until they are old enough to survive on their own.

More Pet Fish Species and Further Research

If you like oscars and are interested in some similar fish species, read up on:

Check out additional fish species profiles for more information on other  fish.