The Ranchu Goldfish is popular throughout the world. They originated in China and then in the later part of the 1800's were further developed in Japan. Having a round broad body and a large bulbous head, they are also known as the Buffalo-head Goldfish, especially in the Orient.
The Ranchu Fancy Goldfish are much prized in the Orient, and are bred there for highly competitive shows. In Chinese shows they are judged from the side, while in Japanese shows they are placed in shallow bowls and judged from the top. Though they are impressive viewed from either direction, it is from above them that you can see their broad back.
Rather than having the long slender body of the Common Goldfish or the Shubunkins, the Ranchu Goldfish is one of the more rounded or egg-shaped fancy gold fish. They closely resemble the Lionhead Goldfish with a compact broad body with short fins. Like the Lionhead, they lack a dorsal fin and will develop the fleshy 'raspberry' head growth. The Ranchu can be distinguished from the Lionhead by a much higher curved contour shape to its back and by its caudal (tail) fin. Its tail fin that splays out to the sides, often being almost horizontal and may have three or four lobes, while the Lionhead's caudal fin is quite similar to that of the Fantail Goldfish.
These fish come in a variety of colors with the most common being bi-colored as in the Gold and White Ranchu Goldfish or the Red and White Ranchu Goldfish. Then there is a Calico Ranchu Goldfish which in Japan is call Edonishiki. They can also be a deep red overall, shaded overall in a reddish to yellow-orange, or have red scales edged in white. They have also been known to be completely white or in some cases black.
The Ranchu Goldfish is considered a rather delicate fish and is not recommended for beginners. Its swimming ability is cumbersome because of its rounded body which is further diminished by the lack of a stabilizing dorsal fin, a trait that is also seen in the Lionhead Goldfish, Water-Bubble Eye Goldfish and the Celestial Eye Goldfish. Many of the elongated goldfish varieties like the the Common Goldfish, Comet Goldfish, the Shubunkin, are not really good companions for the Ranchu Goldfish because they are fast swimmers and too competitive during feeding time. Better tank mates would be the other similarly handicapped, dorsal less goldfish, or the less hardy Telescope Goldfish and Celestial Goldfish. It won't win any races, but if kept with other slow-moving varieties the Ranchu Goldfish should get plenty to eat and do well.