Nigorobuna

Nigorobuna or round crucian carp is a wild goldfish that's native to Japan. The fish swim in Lake Biwa in the Shiga Prefecture. They're traditionally used for the preparation of funazushi, where whole nigorobuna are salted and fermented in beds of cooked rice.

Funazushi is a local specialty of Shiga and it's notorious for its pungent aroma. Round crucian carp is always used to prepare the authentic funazushi that's tender down to the bones, unlike the imitations made with gengorobuna fish.