TankBud

Variety of Goldfish

Ranchu

Carassius auratus

One of 12 varieties of Carassius auratus · See all varieties →

Also known as Buffalo-head goldfish, Japanese lionhead, King of goldfish

FreshwaterFish

Ranchu (Carassius auratus)
Lawrencekhoo · CC BY-SA 4.0

Varieties · Carassius auratus

See all 12 →

Care at a glance

Temperature
61–75°F
16–24°C
pH
6.5–8.0
Adult size
7.1 in
18 cm
Minimum tank
25 gal
95 L
Temperament
Peaceful
Social behavior
Social
Tankmates
With caution
Swim level
Middle
Difficulty
Medium
Breeding
Medium
Rarity
Common
Family
Cyprinidae
Origin
A dorsal finless fancy goldfish refined in Japan from the Chinese lionhead, bred from domesticated Carassius auratus native to East Asian freshwater.

Overview

The ranchu is a fancy goldfish with no dorsal fin, a strongly arched back, a tucked tail and a wen that covers its head. It belongs in a calm tank and is a step up from the easiest goldfish to keep.

Did you know

Ranchu are judged from above in Japanese competitions. Breeders select for the curve of the back and tail as seen from the top rather than the side.

Caring for the ranchu

House one ranchu in at least 25 gal (95 L), and add about 40 L for each extra fish. It swims slowly with a wobbling motion and cannot manage any current, so use gentle filtration. In Japan, where it is prized as a top view fish, it is often kept in shallow tanks viewed from above.

Keep the water cool and clean, at 61 to 75°F (16 to 24°C) and a pH of 6.5 to 8.0. The heavy wen needs clean water to avoid infection.

Feed sinking pellets and vegetables, with the odd frozen food for variety. A goldfish has no stomach, so food passes through it quickly.

Ranchu are peaceful and social, and they want the company of their own kind. Keep them only with other slow fancies such as lionheads, orandas and moors. Watch that faster tank mates do not outcompete a ranchu, since it is a slow, near-sighted feeder. They are moderately difficult to breed.

Good to know

The ranchu is nicknamed the king of goldfish for its show status. The lack of a dorsal fin is a trait fixed by selective breeding. The heavy wen is skin tissue that can grow over the eyes. Like every goldfish, it is Carassius auratus, in the family Cyprinidae.

In the wild

The ranchu was refined in Japan from the Chinese lionhead. Both were bred from domesticated Carassius auratus, a fish native to East Asian freshwater.

From published sources

Tank mates

Each fish here is named as a tank mate for the ranchu by at least two published care guides. Every partner here handles cool water. The tank needs about 20 gallons (75 liters) for the first fancy goldfish and 10 gallons (38 liters) for each extra one.

Sources: Practical Fishkeeping, Aquarium Co-Op, Fishkeeping World, Aquarium Source, Tropical Fish Hobbyist.

Check the full mix in the stocking calculator

Common questions

Is a ranchu a different species from the goldfish?

No. A ranchu is a variety of the goldfish, Carassius auratus. It is kept the same way apart from difficulty, adult size, tank size and temperature.

What size tank does a ranchu need?

A ranchu needs at least 25 gal (95 L). It spends most of its time in the middle.

What does a ranchu eat?

A ranchu eats sinking pellets and vegetables, plus the odd frozen food. It feeds slowly, so make sure faster tank mates do not outcompete it.

How big does a ranchu get?

An adult ranchu reaches about 7.1 in (18 cm).

What fish can live with the ranchu?

Published care guides name weather loach, bristlenose pleco, bulldog pleco and variable platy, among others. Every partner here handles cool water. The tank needs about 20 gallons (75 liters) for the first fancy goldfish and 10 gallons (38 liters) for each extra one.

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