Which genus contains the freshwater angelfish commonly kept in aquariums?

The genus containing the freshwater angelfish commonly kept in aquariums is Pterophyllum.

Pterophyllum is a small genus of South American cichlids known for laterally compressed bodies, tall dorsal and anal fins, and long trailing pelvic fins. These proportions help the fish maneuver among vertical aquatic plants and submerged roots.

The aquarium trade commonly features three recognized species: Pterophyllum scalare, Pterophyllum altum, and Pterophyllum leopoldi. Domestic angelfish strains are often derived mainly from P. scalare and have been bred for many colors and fin shapes.

Freshwater angelfish are frequently confused with marine angelfish. Marine angelfish belong to the family Pomacanthidae and are unrelated despite sharing a common name. Discus are also South American cichlids, but they belong to the genus Symphysodon.