Tsugaru Nishiki are Japanese longfin Ranchus
This variety goes back to 1770, when it was bred in Tsugaru in the far North of Japan, in the prefecture of Aomori. Adapted to a cooler climate, these fish were quite tolerant to cold, more so than other fancy varieties. The original line was lost by the end of WWII. In 1948 only 2 female Tsugaru Nishiki were found to have survived. Breeders re-established the variety by crossing Azuma Nishiki (calico orandas) and Ranchu. They are still rare, even in Japan.
The features of these goldfish are: long flowing double caudal fins and a smooth back without a dorsal fin. Their bodies are longer than those of Ranchus, and less deep. They will develop a wen. This distinguishes them from the Chinese bred Egg Phoenix, a similar variety that has no wen.
Tsugaru Nishikis demelanize late, and will turn red or red and white after up to 4 years.