Koi

, }}, or more specifically , literally "brocaded carp"}}, are colored varieties of carp (''Cyprinus'' sp.) that are kept for decorative purposes in outdoor koi ponds or water gardens.

Koi is an informal name for the colored variants of carp kept for ornamental purposes. There are many varieties of ornamental koi, originating from breeding that began in Niigata, Japan in the early 19th century.

Several varieties are recognized by Japanese breeders and owners, distinguished by coloration, patterning, and scalation. Some of the major colors are white, black, red, orange, yellow, blue, brown and cream, besides metallic shades like gold and silver-white ('platinum') scales. The most popular category of koi is the ''Gosanke'', which is made up of the ''Kōhaku'', ''Taishō Sanshoku'' and ''Shōwa Sanshoku'' varieties. Provided by Wikipedia