The Oscar Cichlid is named after its scientific name ocellatus meaning eye and refering to the bordered "eye" spot near the tail (and sometimes also on the dorsal fin). The oval form with one rounded end and one pointed is reminiscent of Africa's Leopard Climbing Perch, but the Oscar is native to the Amazon Basin from the upper Amazon in Peru through to its outlets in Brazil and Guyana.

The Oscar grows typically to 30cm long and possibly over 40cm. The eye spot markings are thought to deter other fish, especially piranhas, from eating bites out of the fins. Juveniles are camouflaged with wavy stripes and often called Tiger Oscars. Tiger Oscars with stripes as adults are also bred in captivity, together with other bred ornamental varieties (red, albino, flowing fins, etc).

The Southern Oscar, also called the Blackfin, is visually similar to the better known Oscar above, but slightly smaller, the largest being under 25cm long. It is native to the southern Amazon Basin and the Paraguay-Parana Basin.