Although koi are the national fish of Japan, they are not native to the Japanese islands.Koi are believed to have descended from common carp which have evolved from interbreeding between two subspecies of carp; the European Carp, Cyprinus carpio carpio, which originated in Central Europe and Asia, in the Black, Caspian and Aral Seas

Carp have been sourced as a food fish across Europe and Asia for thousands of years, and were farmed in China for sometime before the 5th century B.C.It is believed that these carp were introduced into Japan, either during Chinese invasions or by trade. There are accounts of common carp been kept by a Japanese emperor as early as 200 A.D. They later became domesticated in numerous areas of Asia and Europe.Japanese farmers raised the fish, in the same ponds they used to grow their rice paddies, as a food source to supplement their rice diet, and for sale at local markets. Carp were preserved in salt and were a ready supply of protein for the winter months.In the 17th century, farmers from Yamakoshigo, a village in the Niigata prefecture, began to notice pigmentation irregularities in the form of red and white spots on some of their carp. Instead of eating or selling these fish, the farmers began to keep the coloured carp as pets and, in doing so, became the first koi keepers.

For around one hundred years koi breeding was a leisurely pass-time for the working-class Niigata farmers. The mutated carp were selectively bred, and by around 1830, colour mutations of white, red and yellow had been developed. In the 1880s a number of patterned koi had evolved and many recognised modern varieties had become established.Sometime around the turn of the 20th century the coloured koi were bred with mirror carp. The mirror carp, or “Doitsu-goi”, is a variant of Cyprinus carpio carpio from Germany. It was imported into Japan as a popular food fish, been mainly scale-less they were easier to prepare for the table. The doitsu-goi added to the Niigata koi gene-pool and further expanded the number of possible koi varieties.In 1914, the Niigata koi were exhibited in the Tokyo Taisho Agricultural Exhibition. It is here that the diverse varieties of coloured carp were brought to the attention of the Japanese public.Some of the fish were presented to the Crown Prince Hirohito, the soon to be emperor. These fish were released into the moat surrounding the Emperors palace.

The exhibition sparked a huge interest in the keeping and breeding of koi. It became fashionable for wealthy landowners to buy koi to display in their garden ponds and the hobby soon grew in popularity throughout all Japan. Competitions and exhibitions were organised between breeders, and new colour variances were formed, refined and categorised.Koi breeding declined massively during World War 2. Vast quantities of carp, coloured or not, were claimed by the Japanese government and used to feed its troops. Japan’s major cities were devastated during the latter part of the war and many breeders returned from the war to find damaged homes, ruined businesses and economic turmoil.Fortunately, some of the more prized koi were hidden away in local shrines and temple ponds, it is mainly from these koi that all modern day koi have descended.Japanese post-war reforms, including granting property rights to tenant farmers, and the introduction of free enterprise, helped Japan quickly recover and within a few generations the Japanese economy regained full strength.Koi breeding in Japan now became a serious and full-time hobby. Modern transportation systems were built across the country, and developments such as plastic bags and oxygen helped to expand and modernise the koi industry.In the 1960s many Japanese immigrated to America, Europe and other parts of the world, spreading their expertise of koi breeding and escalating the hobby to become a global activity.There are now koi hobbyist societies in almost every country world-wide, and significant koi shows are held, with high acclaim awarded to ‘Grand Champion’ breeders.