Koi are domesticated ornamental varieties of the common carp Cyprinus carpio. They are not goldfish, just very closely related to goldfish, and the style of breeding and ornamentation has become very similar, probably through the efforts of Japanese breeders to emulate goldfish.
If you travel to Japan and tell friends that you like koi, your friends might invite you to eat the dull grey fish that inhabits the waters of the islands, as in Japanese, the word koi simply means ‘carp’. If you tell them you appreciate Koi, they may lead you and your camera to the pond in the garden. This article is about Nishikigoi, and uses the English word koi to refer to the colourful fish.
While a Chinese book of the Western Jin Dynasty mentions carp with various colours, Koi breeding is generally thought to have begun during the 19th century in the Niigata prefecture of Japan. Farmers working the rice fields noticed that some carp were more brightly coloured than others, they would capture them, and raise them. This would have invariably saved their lives as normally the brighter coloured fish would be more likely eaten by birds and other predators.
By the 20th century, a number of colour patterns had been established, most notably the red-and-white Kohaku. The outside world did not become aware of the degree of development until 1914, when the Niigata Koi were exhibited in Tokyo. Some of them were also presented to Crown Prince Hirohito. At that point, interest in Koi exploded throughout Japan.
Nishikigoi have been called the national fish of Japan. Today, Nishikigoi are bred not only in their place of origin, Niigata, but all over Japan, and are exported all over the world. Nishikigoi continue to gain worldwide popularity as the ultimate pond or garden fish.
As Nishikigoi were developed in Japan, the language of Nishikigoi is Japanese. Japanese is used not only to name the varieties, but also for many of the terms used to describe their colours and traits.
Koi varieties are distinguished by colouration, patterning, and scalation.
Kohaku are white koi with red markings. Probably the most common variety. The hi should be deep red with well defined edges (kiwa) where it meets the white which should be pure and bright. A tancho kohaku is a white koi with a red spot on its head. An inazuma kohaku has a continuous red marking from the head to the tail, but with variation (inazuma means ‘lightning strike’). A nidan (two) kohaku has two red markings, a sandan (three) kohaku has three red markings, and a yondan (four) kohaku has four red markings.
Taisho sanke (known as sanke), hi (red) and sumi (black) on a white background. A maruten sanke has a separate red spot on the head with normal markings on the body. A tancho sanke has a red spot on the head and a white body with black markings.
Showa sanshoku (known as showa), red and white markings on a black background. A hi showa is a predominantly red showa. A kindai showa has a predominantly white pattern. A tancho showa has a red spot on the head and a black body with white markings.
Bekko are white, red or yellow koi with black (sumi) markings. Shiro bekko is a white koi with black markings. Aka bekko is a red koi with black markings (aka is another word for red). Ki bekko is a yellow koi with black markings (rare variety).
Utsurimono are often confused with bekko but are mostly black with white, red or yellow markings. Shiro utsuri is a black koi with white markings. Hi utsuri is black with red markings. Ki utsuri is black with yellow markings (rare variety).
Asagi are blue-grey koi with red along the sides and belly and in the fins.
Koromo literally means ‘robed’. This describes the hi pattern, outlined in a darker colour, which varies with the variety. Ai goromo is a kohaku whose scales have blue borders. Sumi goromo have solid black on the hi markings. Budo goromo have sumi overlaying the hi giving a purple/maroon colour.
Kawarimono accommodates all non-metallic koi that do not fall into the above groups:
Karasugoi is a black koi with white or orange belly. Hajiro is a black koi with white tips to its tail and pectoral fins. Hageshiro is a black koi with white tips to its fins and white head and nose. Kumonryu is a doitsu koi which is black with white markings on its head, fins and body. Aka matsuba is a red koi with black centres to its scales, creating a pine cone effect. Goshiki are white, red, black, blue and dark blue, giving a purplish appearance. Kigoi is a yellow koi. Chagoi is a light brown/olive koi. Soragoi is a blue-grey koi. Midorigoi is a green koi. Benigoi is a deep red koi. Shiro muji is a white koi, aka muji is a red koi. Ochiba shigure is blue-grey with a brown pattern.
The Hobby of keeping Koi spread worldwide after shipping of Koi became both fast and safe for the fish. Koi are now commonly sold in most pet stores, with higher-quality fish available from specialist dealers.