RANCHU 12 cm

The ranchu is a highly regarded fancy goldfish in Japan. Compared to lionheads, ranchus have a more downturned tail and tail fin.^[1] Although similar to lionheads, ranchus have more-arched backs and have much shorter tails that are tucked-in at a 45 degree angle.^[3]

A ranchu has an egg-shaped body with a deep belly that is between 5/8 to 3/4 the length of the fish. This goldfish does not have a dorsal fin and breeding standards require that the back should not have any vestiges of the dorsal fin on it. The back should be rounded and not flat, as in the case of lionheads. The area of the caudal peduncle should curve sharply downwards to meet the tail. The caudal peduncle itself should be broad and neither lengthy or too short (a properly formed caudal peduncle avoids swimming motion impairments to this type of goldfish). The ranchu's tail meets the caudal peduncle at a forty-five degree angle, giving the fish a unique swimming motion. Furthermore, the tail lobes are rounded, and all other finnage are paired.^[2]

The most prominent feature of the ranchu is its head. There must be sufficient space between the eyes, and also from the eyes to the front of the head. The gill cover should figuratively extend quite far towards the tail. The headgrowth should seem to begin from the bottom of the gill cover and move upward.^[3] The headgrowths of young ranchu fry may take at least a year to develop.^[1] Young ranchus possessing broad foreheads and square noses generally produce better headgrowths.^[3] 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.^[2][3] Ranchus with a pale-yellow bodies and bright red heads are rare.^[2]

Ranchus are well-adapted to water quality and pH fluctuations.^[3]