Tosakin Goldfish
Carassius auratus
About this strain
The Tosakin has one of the most unusual tail structures in all of goldfish keeping — the paired caudal fins are fused along the outer edges and spread forward at the tips, creating a fan that curls back toward the fish's head when viewed from above. It's the only goldfish designed to be admired from directly overhead in shallow water. The body is egg-shaped, typically without extreme wen, in red, red-and-white, or calico. Tosakins are delicate, poor swimmers (that curled tail creates drag), and require calm, shallow tanks with gentle filtration. Rare outside Japan.
Origin
Developed in Tosa Province (now Kochi Prefecture) in Japan, likely during the Edo period. Near-extinction occurred during World War II; the variety was revived from a small remaining population by dedicated Japanese breeders afterward.