Goldfish

The goldfish (Carassius auratus auratus) was one of the earliest fish to be domesticated, and is still one of the most commonly kept aquarium fish. A relatively small member of the carp family (which also includes the koi carp and the crucian carp), the goldfish is a domesticated version of a dark-gray/olive/brown carp native to east Asia (first domesticated in China) that was introduced to Europe in the late 17th century.

It may grow to a maximum length of 23 inches (59 cm) and a maximum weight of 6.6 pounds (3.0 kg), although this is rare; most individual goldfish grow to under half this size. In optimal conditions, goldfish may live more than 20 years (the world record is 49 years); however, most household goldfish generally only live six to eight years.