The goldfish (Carassius 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. The mutation that gave rise to the goldfish is also known from other cyprinid species, such as common carp and tench.
Goldfish may 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. In optimal conditions, goldfish may live more than 40 years; however, most household goldfish generally only live six to eight years.
Here’s the longest goldfish:
The world’s longest goldfish is owned by Joris Gijsbers and measured 47.4 cm (18.7 in) from snout to tail-fin end on March 24, 2003 in Hapert, The Netherlands.