Carassius

Carassius is a genus of freshwater ray-finned fish, subfamily Cyprininae, family Cyprinidae, order Cypriniformes, comprising seven recognized species and commonly known as crucian carps, including the goldfish, Carassius auratus, and the type species, the crucian carp, Carassius carassius. The genus has a broadly Eurasian distribution and is thought to have originated further west than the true carps of the genus Cyprinus. Molecular studies suggest Carassius may not be monophyletic, since the genus Carassiodes appears nested within it, and Carassius in turn groups closely with Cyprinus. Species in the genus generally share similar body forms, and the goldfish, long domesticated from wild Carassius stock, is by far the genus's most widely recognized member.