Carassius cuvieri

Carassius cuvieri, the Japanese crucian carp or white crucian carp, is a species in the genus Carassius. It is found in Japan and, as an introduced species, in Taiwan. This fish is closely related to the commonly known goldfish.

The original wild species unique to Lake Biwa is called gengorō-buna(ゲンゴロウブナ (源五郎鮒)), and is listed as an endangered species in the Japanese Red Data Book. There is a larger cultivated variant, with a taller body depth known as hera-buna(ヘラブナ) developed from the original species, cultured in the Osaka area and now released in many areas for sports fishing. It is enjoyed for catch-and-release, since it is not prized for eating.