The Ranchu, also known as the Buffalo (or Ranchu Goldfish in English), holds a special place among valuable and popular aquarium inhabitants in Asia. In countries like China and Japan, there is an entire industry dedicated to breeding this remarkable variety of Goldfish. Interestingly, curious cultural traditions are associated with the Ranchu: in China, it is customary to evaluate them by observing from the side, so they are usually kept in tall aquariums there. In turn, in Japan, the Land of the Rising Sun, tradition dictates admiring the fish from above, which leads to their placement in shallow bowls.
Dangerous to small fish
The Ranchu is a selective form of goldfish with a short, ovoid body and no dorsal fin. A distinctive feature is a strongly curved backline that transitions into the caudal peduncle at a pronounced angle. The head is often covered with well-developed fleshy growths resembling raspberries. The fins are short, and the caudal fin is forked. Adult specimens reach 13–18 cm. The coloration is diverse: red, white, calico, and multicolored variations are found.
The species is an artificially bred variety and does not occur in the natural environment. All modern goldfish originate from the silver crucian carp, which inhabits slow-flowing and still waters of East Asia — China, Korea and Japan. Ranchu are not adapted to life in the wild and require exclusively aquarium conditions.
Ranchu have a calm and peaceful temperament. Due to their body structure, they are slow swimmers, so it is not recommended to keep them with fast or aggressive fish species that can nip fins or steal food. They are compatible with other slow-moving goldfish breeds.
For a single specimen, an aquarium of 75 liters with good filtration is necessary, as these fish produce a lot of organic waste. Rectangular tanks with a large surface area are recommended for efficient gas exchange. It is important to avoid sharp decorations that could damage the head growths and fins. Water parameters: temperature 18–22°C, pH 6.0–8.0, hardness 5–19 dGH.
Ranchu are omnivorous but prone to digestive system problems. Their diet should include both animal and plant components. Special sinking foods are recommended to minimize air swallowing during feeding, which reduces the risk of swim bladder disease. It is beneficial to supplement their diet with plant matter, such as blanched spinach or peas.
Breeding requires experience and adherence to conditions that stimulate spawning. Spawning occurs in pairs or groups, with eggs laid on fine-leaved plants. After spawning, the parents are removed as they may eat the eggs. Fry require frequent feeding and maintaining high water quality for proper body development.
The species is susceptible to gastrointestinal diseases, including bloat and swim bladder dysfunction, often caused by improper feeding. Bacterial infections of the head growths are also possible with poor water quality. Prevention involves maintaining stable environmental parameters and regular water changes.
When choosing a fish, pay attention to its activity, the absence of visible damage, ulcers, or plaque on the body and growths. A healthy specimen should swim evenly, without tipping to one side or floating to the surface. It is recommended to avoid specimens showing signs of emaciation or an unnaturally bloated abdomen.
There are no pair reviews for this species yet — check tankmates in the matcher.
All tankmatesThe water suits 196 of 208 plants in the catalogue — the easiest ones are shown first.
Afzelius's AnubiasAnacharisAnubiasBrazilian PennywortDwarf CloverDwarf CloverDwarf HygrophilaDwarf SagittariaDwarf ValGuppy GrassHornwortJava FernJava MossMoneywortMud SwordNarrow Leaf AnacharisNarrow-leaf CloverStringy MossSüsswassertangTaiwan MossTape GrassTemple PlantUssuri WatermilfoilWater Wisteria
Matching water does not mean the plant will stay intact.
The essentials: size, tank volume, water parameters and care
An adult reaches 13–18 cm in length. Plan the tank around the maximum size: the fish quickly outgrows a cramped setup.
The recommended volume is 75 L. A smaller tank speeds up nitrate build-up and raises stress levels.
Temperature 18–22 °C, pH 6–8, hardness 5–19 dGH. Stability matters more than exact values: sudden swings are harder on the fish than a small deviation from the ideal.
Around 15 years when kept properly. Lifespan depends directly on tank volume, water quality and a varied diet.
Temperament: semi-peaceful (dangerous to smaller ones). Not a predatory species, but small fish that fit in its mouth will eventually be eaten.
Recommended setup: mixed (solitary / pair / group). Ignoring this is a common cause of stress and disease.
Diet type: any (universal). Feed small portions that are finished within a couple of minutes — overfeeding does more harm than underfeeding.
The scientific name of the species is Carassius auratus, family Cyprinids (Cyprinidae). It also appears in the literature as: Carasius auratus, Carassius buergeri, Carassius burgeri.
Matched by family, categories and overlapping keeping conditions
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