Calico Ranchu - Carassius auratus

Calico Ranchu (Carassius auratus)

The Calico Ranchu is a distinctive fancy goldfish variety admired for its rounded body, smooth arched back and complete absence of a dorsal fin. Its calico colouration can include combinations of white, orange, red, black, blue-grey and metallic or pearlescent tones, making every individual visually unique. Peaceful and highly decorative, Ranchu are best suited to spacious, well-filtered aquariums with other slow-swimming fancy goldfish.

Common Name:
Calico Ranchu, Ranchu Goldfish

Scientific Name (Latin):
Carassius auratus

Maximum Size:
Approximately 15–20 cm

Water Type:
Freshwater

Origin / Natural Habitat:
The Calico Ranchu is a selectively bred fancy goldfish variety descended from domesticated Carassius auratus.

Ranchu have been developed specifically for ornamental keeping and are recognised for their deep rounded body, curved back profile, short tail and characteristic head growth.

Water Parameters:
Temperature: 18–24°C
pH Range: 6.8–8.0
Hardness: Moderate to Hard
Ammonia/Nitrite: 0 ppm
Nitrate: Kept low with regular maintenance

Temperament:
Peaceful

Calico Ranchu are calm and sociable fish that are best kept with other fancy goldfish of a similar size and swimming ability.

Avoid housing them with aggressive, fin-nipping or very fast-moving fish that may intimidate them or outcompete them at feeding time.

Diet:
Omnivore

Offer a varied diet based around high-quality sinking goldfish pellets or granules.

Supplement with foods such as frozen or live daphnia, brine shrimp and bloodworm, together with suitable vegetable-based foods.

Sinking foods are generally preferable for fancy goldfish, as they reduce excessive surface feeding and air swallowing.

Minimum Tank Size:
Approximately 120 litres for a small group, with additional space required as the fish grow.

Fancy goldfish produce a considerable amount of waste, so generous aquarium volume and strong biological filtration are important for maintaining stable water quality.

Behaviour & Activity:
The Calico Ranchu is a relatively slow and gentle swimmer that spends much of its time exploring the aquarium and searching the substrate for food.

Its rounded body shape and lack of a dorsal fin make it less agile than common or single-tailed goldfish.

Provide plenty of unobstructed swimming space and avoid strong currents that may make swimming difficult.

Community Suitability:
Community Fish

Best kept with other peaceful fancy goldfish such as Orandas, Lionheads, Ryukin and similarly slow-swimming varieties.

Avoid keeping them with common goldfish, Comets or other very fast feeders where competition for food may become a problem.

Special Requirements or Care Notes:
Excellent filtration is essential because goldfish have a relatively high biological load.

Regular partial water changes should be carried out to maintain low nitrate levels and stable water chemistry.

The head growth can continue developing as the fish matures and should be observed regularly to ensure it remains healthy and does not interfere with feeding or vision.

Use smooth gravel, rounded décor or fine sand to reduce the chance of accidental injury.

Avoid sudden temperature changes and maintain good oxygenation, particularly in warmer conditions.

Because this is a calico variety, individual fish can vary considerably in colour balance, spotting, metallic sheen and pattern distribution.

Suitable for:
Beginner to Intermediate

Availability:
Regularly available

All images are a visual representation of the fish you will receive, made to be as accurate as possible. Please note that Mother Nature is a wonderful thing, and variation in patterns and colours will occur — that is part of the unique beauty of these animals.