One of the most pupular commonly kept aquarium fish is a goldfish. Goldfish (Carassius auratus auratus) was one of the earliest fish to be domesticated of a dark-gray/olive/brown carp native to east Asia (first domesticated in China) . They are relatively small member of the carp family (which also includes the koi carp and the crucian carp). Then in the late 17th century goldfish was introduced to Europe.
The goldfish can grow to a maximum length of 23 inches (59 cm) and a maximum weight of 9.9 pounds (4.5 kg), although this is rare. Most individual goldfish grow to under half this size. Most household goldfish generally only live six to eight years, but in optimal conditions, goldfish may live more than 40 years.
