Astronotus is a genus of South American fish from the family Cichlidae. The genus is one of three genera which make up the tribe Chaetobranchini. There are two species in the genus (listed below), both of which are found in the Amazon Basin, while one of two also is found in the Paraná and Paraguay rivers. Astronotus species grow to 35 cm in size, and are monomorphic. They are opportunistic omnivores and consume a range of smaller fish, crustaceans, mollusks and other invertebrates in the wild. In contrast, Astronotus crassipinnis is rarely exported and is not seen often in the aquarium trade.