The (also Maruko) is a hooded variety of goldfish native to China. It is referred to as the 'king of goldfish" by the Japanese. Maruko more commonly refers to the egg-fish goldfish. Species origins and evolution The Ranchu is a member of the Japanese development of the lionhead. They are the direct outcome of crossbreeding experiments with Chinese lionhead specimens. Morphology Ranchus have egg-shaped bodies and deep bellies – between 5/8 to 3/4 the length of the fish. These goldfish have no dorsal fin. Breeding standards require that the back should not have any vestiges of the dorsal fin on it. The back should be rounded, not flat like a lion head. The area of the caudal peduncle should curve sharply downwards to meet the tail. The caudal peduncle itself is broad. A properly formed caudal peduncle avoids swimming motion impairments. The ranchu's tail meets the caudal peduncle at a 45-degree angle, giving the fish a unique swimming motion. The tail lobes are rounded, and all other fins are paired. Compared to lionheads, ranchus have a particularly down-turned tail and tail fin. Ranchus have arched backs and much shorter tails, which are tucked in at a 45-degree angle. Ranchus' most prominent feature are their heads. Sufficient space between the eyes, and also from the eyes to the front of the head must be preserved. The gill cover should extend towards the tail. The head growth should seem to begin from the bottom of the gill cover and move upward. The head growths of ranchu fry may take at least a year to develop. Fry possessing broad foreheads and square noses generally produce better head growths. Mature ranchus can reach between 6 and 8 inches (15 to 20 centimeters) in length. Ranchus may come in orange, red, white, red-and-white, blue, black, black-and-white, black-and-red, natural, and chocolate coloration. Scalation may either be metallic, nacreous (calico) or matte. Ranchus with pale-yellow bodies and bright red heads are rare. Ranchus are well-adapted to fluctuations in pH levels and water quality. Classification, deportment and conformation Japanese, Thai, American, and British ranchu breeders, as well as many goldfish societies, adhere to two strict viewing classifications, namely the top-view ranchu comportment and the side-view selection criteria. Japanese aesthetic standards for ranchus are more exacting. Ranchus are often compared to sumo wrestlers, as the ranchu is a rounded fish with a head-growth (known as a "bramble-head"). However, traditional