The oscar (Astronotus ocellatus) is a species of fish from the cichlid family known under a variety of common names. It is native to tropical South America, where the species naturally resides.
A. ocellatus examples have been reported to grow to about 18 inches in length and 3.5 lbs. in weight. The wild-caught forms of the species are typically darkly coloured with yellow-ringed spots or ocelli on the caudal peduncle and on the dorsal fin. These ocelli have been suggested to function to limit fin-nipping by piranha, which co-occur with A. ocellatus in its natural environment. The species is also able to rapidly alter its colouration, a trait which facilitates ritualised territorial and combat behaviours amongst conspecifics. Juvenile oscars have a different colouration from adults, and are striped with white and orange wavy bands and have spotted heads.
Wild oscars also consume shrimp, snails, insects and insect larvae, as well as fruits and nuts on a seasonal basis. The species also has an absolute requirement for vitamin C, and develops health problems in its absence. Captive oscars generally eat fish food designed for large carnivorous fish: crayfish, worms, and insects (such as flies, crickets and grasshoppers).
Oscars will often lay claim to an area of the aquarium and will be very aggressive towards other fish encroaching on their newly established territory inside the aquarium or lake. The size of the territory varies depending on the size and aggressiveness of the fish based on its surroundings. Once the oscar establishes a territory, it will vigorously defend it by chasing away other fish.
Hardness: Moderately hard
Min tank size:75 Gallons