Koi fish are actually carp, that have been bred selectively for their special colors and markings. Carp are native to Europe and parts of Asia and they are fresh water fish, that are highly adaptive to different environments.

This adaptability made them excellent for captive breeding for food. They could also be introduced to new regions quite easily.

Origins of Koi Fish

Koi fish, as we know them, were first bred as ornamental fish in Japan in the 1820’s. Because carp have natural color mutations, the Chinese started breeding them to produce desired, decorative colors. This led to the origin of the Goldfish.

Carp were introduced into Japan as a food fish, but were selectively bred for color in the town of Ojiya, on Honshu island. The word “Koi” is simply Japanese for “carp”.

Over the next 80 years, various koi fish emerged with recognizable patterns. The rest of the world knew very little about the phenomenon; it was only in 1914 that outsiders first saw koi fish, at the annual exposition in Tokyo.

The koi were an instant hit and its popularity spread throughout Japan and within a few years, they were available in pet shops in many different countries. Currently, they are readily available in many pet shops, but the sought-after breeds are still imported from Japan.

Koi Characteristics

Goldfish and Koi were bred from the same species of common carp. The biggest difference between the two is size and coloring. If koi and goldfish interbreed, their offspring are sterile. Koi fish are characterized by their distinctive markings, colors and patterns. Every kind of pattern and color scheme that has been intentionally bred, has resulted in a specific kind of koi fish.

Koi that do not have well-defined patterns, or have interbred with other kinds of koi can still be incredibly beautiful, but are not worth the same as their pure-bred siblings. They can grow to be really large. Their size is governed by how large their pond or lake is, and by how many others are living in it.

Largest specimen ever – 30 lbs?

Typically, Koi exhibit the following colors, in different arrangements: white, gold, red, orange, black and blue. They can live for well over a hundred years, if looked after carefully. When koi have been released into the wild, their markings and coloring reverts back to normal carp characteristics within a few generations.