Common Name: Red Oscar, Oscar
Scientific Name: Astronotus Ocellatus
Average Adult Fish Size: 12 – 14 inches / 30.5 cm – 35.5 cm
Place of Origin: Oscars are native to Brazil, French Guinea, Columbia, and Peru and occur frequently in the Amazon River and surrounding basins.
Typical Tank Setup: A mostly open aquarium with some rock work. Large, well rooted plants like Giant Vallisneria, if kept protected by heavy rock work, will also work.
Recommended Minimum Aquarium Capacity: 55 gallon / 210 litre for one, 75 gallon / 300 litre or larger for a pair.
Compatibility: Temperament ranges from passive to mildly aggressive. Best if kept with other similar sized fish. Oscars will eat any fish that will fit in their mouth!
Temperature: 72 – 80 Deg. F / 22 – 27 Deg. C
Water Chemistry: pH 6.8 – 7.6 with ideal being 7.2.
Feeding: Flaked, frozen, and pelleted food when smaller, and larger pellets along with chunks of frozen food when larger. Oscars will eat live fish, but this is not the best diet for them as diseases are commonly introduced when using live feeder fish as food. Oscars diets can also be supplemented with krill, freeze dried shrimp, bloodworms, or vegetables like peas, lettuce, cucumber, zucchini. Like most fish, a varied diet is best.
Sexing: Males are usually larger and more colorful, but while these characteristics may help an experienced hobbyist, venting is the only sure way to determine gender with Oscars.
Breeding: When breeding Oscars become very territorial and other species should be removed if possible. Oscars will often perform a courtship where they will lip lock for hours at a time, if during this time one backs down, they are usually attacked. Also, occasionally during mating the males will kill the females. Breeding Oscars is easily achieved once paired. Provide a medium sized piece of slate or other flat rock for breeding. Oscars mature after 1 year of age and can continue to breed for the remainder of their life. Normal life spans for Oscars in an aquarium setting with good water quality and proper nutrition is 7-8 years.
Additional Information: Oscars are messy fish with large appetites. Adequate filtration and frequent water changes are required to keep this fish healthy and/or in breeding condition. Oscars are kept by many aquarists because they are seen as a very intelligent and outgoing species of cichlid. They can be as aggressive as other large South Americans that are found in nature with them, but are not always. Oscars can differentiate between their owners and others and are often docile enough to be petted after feeding. Play for Oscars includes moving rocks or plants around the aquarium. This is another reason why adequate filtration and frequent water changing is necessary.