The Japanese white crucian carp, also known as Japanese carp, white crucian carp, or gengoro-buna, is a species of freshwater fish in the carp family. It is found in Japan and, as an introduced species, in several other countries in Asia. This fish is closely related to the commonly known goldfish.

Nigoro-buna, sometimes called round crucian carp, is a type of wild goldfish or related cyprinid endemic to Japan. Its habitat is limited to Lake Biwa, its tributaries and distributaries, and irrigation canals, in the Shiga Prefecture, northeast of Kyoto.