C. a. auratus trinomial = Carassius auratus auratus trinomial_authority = (Linnaeus (Carolus Linnaeus), 1758)

The goldfish (Carassius auratus auratus) is a freshwater fish in the family (Family (biology)) Cyprinidae of order (Order (biology)) Cypriniformes. It was one of the earliest fish to be domesticated (domestication), and is one of the most commonly kept aquarium fish (List of freshwater aquarium fish species).

A relatively small member of the carp family (which also includes the koi carp (koi) and the crucian carp), the goldfish is a domesticated version of a dark-gray/olive/brown carp (Carassius auratus) native to east Asia. It was first domesticated in China more than a thousand years ago, and several distinct breeds have since been developed. Goldfish breeds vary greatly in size, body shape, fin configuration and coloration (various combinations of white, yellow, orange, red, brown, and black are known).

Goldfish may grow to a maximum length of in to cm23 and a maximum weight of lb to kg9.9citation neededdate=June 2010 although this is rare; most individual goldfish grow to under half this size. In optimal conditions, goldfish may live more than 40 years; however, most household goldfish generally live six to eight years.