Which freshwater fish is commonly called the oscar?

Astronotus ocellatus is the freshwater fish commonly called the oscar.

The oscar is a large South American cichlid native to the Amazon, Orinoco, and Essequibo river basins. It is popular in aquariums because it learns to recognize its keeper, accepts many foods, and displays strong territorial behavior.

Wild oscars are usually dark with orange or red markings, although aquarium breeding has produced forms with varied patterns and colors. The species can grow much larger than many community-aquarium fish, so adults require spacious tanks and strong filtration.

The common name “oscar” is used in the aquarium trade, while Astronotus ocellatus is the accepted scientific name. It is sometimes confused with peacock bass or angelfish because all are South American cichlids, but they belong to different genera.