The Ranchu goldfish and Lionhead are often mentioned together in some publications as if they were the same goldfish variety. They are not.
The Ranchu is a Japanese goldfish variety, the Lionhead is Chinese.
The positions of the caudal peduncle and caudal fins of the Ranchu are different to a Lionhead goldfish. These two features are what distinguish the two varieties.
The Ranchu back is more arched, with the caudal peduncle having a distinct downwards tilt. The Lionhead's back is less curved, and the caudal peduncle is more square to the body.
The caudal fins of the Ranchu are very spread, almost horizontal to the body. The caudal fins on the Lionhead are less spread, looking more like most other twin caudal fin varieties.
The hood on a Ranchu should cover three areas, and the amount of growth should be the same:
Hood development in the Ranchu isn't as great as seen in the Lionhead.
The hood development should start to appear about 120 days after hatching. Maximum development can take four to five years, when large areas may be shed. Males produce better hoods than females.
Hood development is greatly affected by the way the fish is raised. Water quality, temperature and diet all play a part. It is believed that water with algae present hinders the development of the hood.
Ranchu fry need to be viewed from the side in an aquarium as soon as dorsal fins start to show to allow fish developing them to be culled out. Back profiles can also be viewed for smoothness and contour at the same time.
Country of Origin: Japan
Maximum size (body length): 5 inches (125mm)
Caudal Fin: Paired, must be short, forked and very spread
Dorsal Fin: Absent
Anal Fin: Paired
Scale Group: All scale groups but most often Metallic
Distinguishing traits: A raspberry like
covering over the head area including the gill plates and cheeks
Breeding: The hood development can be so great that the eyes become covered. If the male's eyesight is hindered by hood growth, an uncluttered breeding container is required so the female doesn’t have the opportunity to hide.
Male/female differences are less obvious outside the breeding season because of the short round body shape. Often the female will have a slimmer body shape than the male giving the impression she is male.
The white tubercles that appear on the male’s operculum (gill plates) are underneath the hood so the leading edges of the pectoral fins in the breeding season are the only sure sign of gender.
The absence of the dorsal fin isn’t a stable characteristic with Ranchu goldfish, similar to the Lionhead . If 40 percent of the fry lack a dorsal fin, that is considered a very good percentage.
Special requirements: Not to be kept with normal eyed goldfish if eyesight is impaired by hood development.