Some of you may be tempted to keep Cyprinus carpio (Koi Carp) in an aquarium and we would like to advise against this. Koi are potentially large fishes best housed in large purpose-built ponds with powerful filtration systems.
Kept by man for many, many years, Carassius auratus (the Goldfish) is probably the best known of all aquarium/pond fishes. The wild form of this fish is a dull green to brown animal with little to recommend it as a potential aquarium fish, but a mutation occurred which developed lovely gold patches on the body which eventually turned the whole fish gold.
