Ranchu Goldfish

About the Ranchu Goldfish

The Ranchu Goldfish is widely regarded as the "King of Goldfish" and is one of the most prestigious fancy goldfish varieties in the world. Originating in Japan, the Ranchu is instantly recognisable by its rounded egg-shaped body, prominent head growth (wen), and complete lack of a dorsal fin, giving it a smooth, elegant silhouette unlike any other goldfish.

Available in a wide range of colours including orange, red, white, calico, black, and bi-colour varieties, Ranchus are highly prized for their graceful swimming style and gentle temperament. They are social fish that thrive when kept with other fancy goldfish of similar swimming ability.

Ranchu Goldfish require spacious aquariums with excellent filtration and stable water quality. Their rounded body makes them slower swimmers than common goldfish, so they should not be housed with faster varieties that may outcompete them for food. A varied diet of premium goldfish pellets, gel foods, blanched vegetables, and frozen foods will help support healthy growth and the development of their characteristic wen.

Elegant, personable, and full of character, the Ranchu Goldfish is an outstanding centrepiece for dedicated fancy goldfish aquariums.

Quick Care Guide

Scientific Name

Carassius auratus

Common Name

Ranchu Goldfish

Origin

Captive-bred ornamental variety originating from Japan

Adult Size

15–20 cm

Temperament

Peaceful

Diet

Omnivore

Minimum Tank Size

150 Litres (for a pair)

Temperature

18–24°C

pH

6.8–7.8

Water Hardness

5–18 dGH

Difficulty

Beginner to Intermediate

Lifespan

10–20 Years

Suitable For

Fancy goldfish aquariums and indoor ponds

Frequently Asked Questions

Why don't Ranchu Goldfish have a dorsal fin?

The Ranchu has been selectively bred over centuries to develop a smooth, rounded back without a dorsal fin, giving it its distinctive appearance.

Can Ranchu Goldfish live with tropical fish?

No. Ranchus prefer cooler water and are best kept with other fancy goldfish rather than tropical species.

What do Ranchu Goldfish eat?

They thrive on high-quality sinking goldfish pellets, gel foods, blanched vegetables such as peas and spinach, frozen bloodworms, brine shrimp, and daphnia.

How large do Ranchu Goldfish grow?

Most Ranchus reach between 15 and 20 cm, although exceptional specimens can grow larger with proper care.

Can Ranchu Goldfish live in ponds?

Yes, provided the climate is suitable and they are housed with other fancy goldfish in predator-free ponds with excellent water quality.

Common Mistakes

Feeding floating foods

Floating foods can cause these dorsal-less goldfish to swallow excess air, increasing the risk of buoyancy issues. Sinking foods are strongly recommended.

Keeping them with fast-swimming goldfish

Common, Comet, and Shubunkin Goldfish often outcompete Ranchus for food.

Poor filtration

Goldfish produce significant waste and require powerful filtration with regular water changes.

Overfeeding

Excess feeding can lead to obesity, digestive issues, and swim bladder problems.

Keeping them in small bowls

Ranchu Goldfish require spacious, well-filtered aquariums to thrive and should never be kept in bowls.