Orange-white Koi at the Artis Royal Zoo (also known as Natura Artis Magistra), Amsterdam (Holland)

Koi or more specifically Nishikigoi (literally "brocaded carp" in Japanese), are coloured varieties of the Amur Carp that are kept for decorative purposes in outdoor Koi ponds or water gardens. Koi is an informal name for the coloured variants of C. rubrofuscus 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 the Japanese, distinguished by colouration, patterning, and scalation. Some of the major colours are white, black, red, orange, yellow, blue, brown and cream.