Watonai Goldfish
Carassius auratus
About this strain
The Watonai is a hybrid variety with a Ryukin-style humped body and a single, forked tail — a combination that doesn't appear naturally in either parent variety. It's more robust than most fancies thanks to the single tail, while still having the body depth and dorsal hump that signal its fancy ancestry. Coloration is typically red, red-and-white, or calico. An intermediate choice for keepers who want fancy body aesthetics without the full fragility of a twin-tailed fish. Relatively uncommon in mainstream retail; you may need to seek out specialist breeders.
Origin
Developed in Japan as a deliberate cross between Wakin (single-tail) and Ryukin (double-tail) goldfish. The variety has been known in Japanese goldfish culture for several decades, though it remains a specialty variety with limited mainstream distribution.