 The most common species in hobbyist aquaria is "Pterophyllum scalare" from the Amazon River basin in tropical South America, known in the trade as the "angelfish".Other popular or readily available species include the oscar ("Astronotus ocellatus"), convict cichlid ("Archocentrus nigrofasciatus") and discus fish ("Symphysodon").Some cichlids readily hybridize with related species, both in the wild and under artificial conditions.