Why is my ranchu floating upside down?
Almost always gut trouble, not disease. Air gulped with floating food, or constipation, tips the short body over. Stop feeding for 48 hours, then offer a blanched skinned pea, and switch to sinking food. If it keeps happening, check that the water is warm enough and nitrate is low.
Can ranchu live in a bowl?
No. Even one adult needs about 75 liters (20 gallons) and a cycled filter. A wide, shallow plastic tub with a sponge filter is cheap, and it is closer to how breeders keep them than a bowl or a tall tank.
Do ranchu need a heater?
Usually not. They are comfortable from 65 to 75 °F (18–24 °C). What they hate is rapid change, so a heater set as a floor at 65 °F can help in a cold room or during water changes.
How long do ranchu live?
Ten to fifteen years is normal with good water, and older fish are documented. Most that die young die in the first months from ammonia in an uncycled tank.
What is the difference between a ranchu and a lionhead?
Both lack a dorsal fin and grow a wen. The lionhead has a straighter back and a tail held higher, and comes from Chinese breeding. The ranchu has a deeper curved back and a tucked tail, and is the Japanese refinement. Shops mix the labels up constantly.
Can I keep ranchu with other goldfish?
With other slow, round-bodied types, yes: lionheads, orandas, pearlscales. Not with comets, commons or shubunkins, which will eat everything first, and never with tropical fish.
Will the wen grow bigger?
Yes, from about one year old and for several years after. Good genetics come first, then protein-rich food, warmer water in the low 70s °F, and clean water. Trimming is done by some breeders but is not something to try at home.