Angelfish , any of various unrelated fishes of the order Perciformes. The angelfishes, or scalares, popular in home aquariums are members of the genus Pterophyllum and the cichlid (q.v.) family. They are thin, deep-bodied fishes with elongated dorsal, anal, and pelvic fins. Depending on the authority, one to three species may be recognized: P. scalare, P. eimekei, and P. altum. Angelfishes are native to the freshwaters of tropical South America and may grow to a length of about 15 cm (6 inches). They are commonly silvery with vertical dark markings but may be solid or partially black. They are carnivorous and take care of their eggs and young.