Ryukin Goldfish, Good Breeding means Quality Fish
wikipedia


The Ryukin Goldfish is a variety of fancy goldfish. The most notable
feature of this variety is a hump in its back -- generally, the
higher or more pronounced the hump is, the better the quality of
Ryukin the fish is. Ryukin have more pointed heads than other
varieties of goldfish, and are bred to show other such desirable
traits as doubled caudal and anal fins.


Due to the modifications bred into this variety, they do not swim
quite as well as other, less modified varieties such as the
Shubunkin and Comet (goldfish). However, Ryukin have no
eye-modifications, and thus they are at an advantage over such
varieties as the Telescope Eye, Black Moor, and the Celestial Eye.

Picture Ryukin Goldfish





When choosing tank mates, this should be taken into account,
as goldfish will gladly glut themselves upon everything in sight,
including food intended for a tank mate. They will also nip the
fins of anything that gets in their way, whether it can see them
properly or not.