HOW ARE GOLDFISH AND KOI DIFFERENT?
Goldfish and Koi may have some similarities, but they are definitely two different fish. The Goldfish (Carassius auratus) is over a thousand years old, and was created by the selective breeding of a type of fish known as the Prussian Carp. The plan was to develop different color mutations, and this idea was very successful. The changes in the fish were so distinct that the Prussian Carp and the Goldfish are now thought of as two completely different species of fish. Goldfish migrated to Japan and Europe during the sixteenth and seventeenth centuries.
The Common Carp and the Koi
The background of the Koi contains a fish known as the common Carp. In fact, the Koi is a common Carp (Cyprinus carpio) that has been severely culled over time for color and pattern. Contrary to popular belief, the Koi is still a common Carp. All that is needed to prove this is allowing a group of carp to breed with each other at will for several generations. The natural and original color of these fish will reappear by the second or the third generation.
Goldfish Vs Koi
Goldfish are not as large as Koi. Their bodies come in an array of different shapes, and their fins and tails can be put together in several diverse configurations. Koi share a universal body shape, but have a wider variety of body colors and patterns than the common Goldfish. Koi also have a slender barbell on their lip that resembles a whisker.
Even though Goldfish and Koi may look somewhat similar, especially when they are young, remember that each comes from a different genus of the carp. Goldfish and Koi are able to interbreed, and will produce young fish, but these fish are always sterile.