Fish have been kept in ponds for thousands of years. Whether as a food source or merely as pets, people have enjoyed keeping them and breeding them to create many varieties distinct from their wild ancestors. Most goldfish are more colourful than the carp from which they descended. They have been selectively bred for all sorts of morphological differences; colour (shubunkin) fin shape and size (fantail, black moor, comet) body shape, and even for extra body parts as is the case in the lionhead, Celestial, bubble eye and pom-pom goldfish

Other types of goldfish include Ranchu, Oranda and Ryukin

One of the most interesting fish to aquarists is the Koi carp, a fish with a large number of dedicated keepers worldwide.