The Collaborative International Dictionary of English v.0.48:

Goldfish \Gold"fish`\, n. (Zool.)
   (a) A small domesticated cyprinoid fish (Carassius
       auratus); -- so named from its color. It is a native of
       China, and is said to have been introduced into Europe in
       1691. It is often kept as an ornament, in small ponds or
       glass globes. Many varieties are known. Called also
       golden fish, and golden carp. See Telescope fish,
       under Telescope.
   (b) A California marine fish of an orange or red color; the
       garibaldi.
       [1913 Webster]

WordNet (r) 3.0 (2006):

Carassius auratus
    n 1: small golden or orange-red freshwater fishes of Eurasia
         used as pond or aquarium fishes [syn: goldfish,
         Carassius auratus]