information:extraction, quality:correction
Varieties

According to Zen Nippon Airinkai, a group that leads the breeding and dissemination of koi in Japan, there are more than 100 varieties of koi created through breeding, and each variety is classified into 16 groups. Koi varieties are distinguished by coloration, patterning, and scalation. Some of the major colors are white, black, red, yellow, blue, and cream. Metallic shades of gold and platinum in the scales have also been developed through selective breeding. Although the possible colors are virtually limitless, breeders have identified and named a number of specific categories. The most notable category is Gosanke (御三家), which is made up of the Kōhaku, Taishō Sanshoku, and Shōwa Sanshoku varieties.

New koi varieties are still being actively developed. Ghost koi developed in the 1980s have become very popular in the United Kingdom; they are a hybrid of wild carp and Ogon koi and are distinguished by their metallic scales. Butterfly koi (also known as longfin koi, or dragon carp), also developed in the 1980s, are notable for their long and flowing fins. They are hybrids of koi with Asian carp. Butterfly koi and ghost koi are considered by some to be not true nishikigoi.

The major named varieties include: