Nishikigoi is the Japanese word for ornamental varieties of domesticated common carp.
The word combines Japanese terms associated with brocaded or richly colored carp. In English, these fish are usually called koi. They descend from the common carp, Cyprinus carpio, and were selectively bred for vivid colors, patterns, and body shape rather than primarily for food.
Modern ornamental carp breeding developed especially in Japan’s Niigata region during the nineteenth century. Early breeders selected mutations that produced red, white, black, yellow, and other color combinations. Named pattern varieties include Kohaku, Sanke, and Showa, but those are individual classification types within the broader koi tradition.
Nishikigoi should not be confused with every colorful pond carp: the term specifically refers to ornamental domesticated carp. Common carp used mainly as food or wild-type carp are related, but they are not automatically classified as nishikigoi.