Ornamental aquarium and pond fish (Carassius auratus) of the carp family, native to East Asia but introduced into many other areas. The goldfish was domesticated by the Chinese at least as early as the Song dynasty (960–1279). It is naturally greenish brown or gray, but its colour varies. Selective breeding has produced more than 125 breeds, including the veiltail, with a three-lobed, flowing tail, and the common, pet-shop comet. They feed on plants and small animals and, in captivity, on small crustaceans and other foods. They have become naturalized in many parts of the eastern U.S.