The king of goldfish, seen from above.

Ranchu are bred to be viewed looking down into a shallow tub: the arched back, the hooded head, the tail tucked flat. Everything on this site follows that view, from the anatomy chart to the way we size a tank.

Start with the care guide How many fit my tank?

Sarasa (red-and-white) and solid red ranchu, top view · illustration

20 gal / 75 Lfirst fish, then +10 gal each
65–75 °F18–24 °C, stable
pH 7.0–8.0hard, alkaline water
5–8 inadult body length
10–15 yrslifespan with good care
No dorsal finbred out over 300 years
Guides

Start here

Care guide

Tank size, water, feeding and the four things that cause almost every problem.

Read the care guide Anatomy

What a Japanese judge looks at: wen, back curve, tail joint, outline from above.

See the diagram Varieties

Sarasa, red, black, calico, blue, chocolate. And the Japanese vs Thai split.

Browse colors Life stages

Tosai, nisai, oya: what the words on a breeder's price list mean.

Learn the terms Tank calculator

Enter your tank or tub and get a stocking number that checks surface area too.

Open the calculator Buying guide

What to check in the shop, what ranchu cost, and where the money goes.

Before you buy
Questions

Answers keepers search for

Why is my ranchu floating upside down? Ranchu vs lionhead: what is the difference? Can ranchu live in a bowl? How long do ranchu live? What can live with ranchu? How do I get the wen to grow? Do ranchu need a heater? How much is a ranchu goldfish? How big do ranchu get? What do ranchu eat? Do ranchu get lonely? Are they aggressive? How to breed ranchu Ranchu vs oranda Why is my ranchu turning black? Ranchu diseases and health problems Where to buy ranchu Ranchu goldfish in Animal Crossing All questions