This fish has been around in China and Japan for many years. There are now different versions of this variety available, the choice in tail length and colour being the options. There is a normal tail, short tail and the longer flowing tail. The original standard tail is still very popular with many but now the short tail version has become available more and more people are warming to this variety. The Ryukin defined by the hump on its back is often confused with the Fantail, of course the main difference is the presence of a defined hump as the Ryukin gets older.
The standard tail presents a really nice looking fish and adapt very well in all size Aquariums, large or small, but if you are looking for a bit of a powerhouse type fish then look no further than the Short tail Ryukin. Less graceful than the normal tail and full of its own importance the short tail looks a different fish. However not generally a bully in any way to other fish. I’ve only found them to be slightly aggressive when in spawning condition the male might chase others but the answer then (if spawning not required) is to remove the male. The Longer Flowing tail version really is the complete opposite to the short tail and the normal tail sits in the middle of this lovely Fancy Goldfish Variety