Jikin

The Jikin is a rare selectively bred form of goldfish, developed in Japan. Its body has a streamlined shape, similar to a Wakin, but shorter and wider. The main feature of the breed is its caudal fin, which is divided into four lobes that form an “X” shape when viewed from behind. Due to this characteristic, the fish is often called the “peacock tail.” The standard coloration implies a white body with bright red or orange areas on the lips, gill covers, and all fins. Adult specimens reach a size of about 15 cm.

The species is an artificially bred selective form and is not found in the wild. Historically, the breed developed in Japan, in the Nagoya region (Aichi Prefecture), where it is still considered a cultural heritage and a protected species. In aquarium conditions, it requires stable water parameters consistent with the keeping of other ornamental goldfish varieties.

The Jikin has a peaceful and calm temperament. It is an active fish that coexists well with its own kind and other non-aggressive species of similar size. Intraspecific aggression is practically absent. Due to the peculiarities of their fin structure and their slowness compared to ordinary fish, Jikins are best kept in a species-specific tank or with other calm goldfish.

For keeping one specimen, an aquarium of at least 75 liters is required, but more spacious tanks are preferable. Water parameters: temperature 18–22°C, pH 6.0–8.0, hardness 5–19 dGH. Powerful filtration and regular water changes are necessary, as the fish produce a lot of organic waste. Fine gravel or sand is best used as substrate to avoid fin damage. Lighting should be moderate, with open swimming areas.

The Jikin is an omnivorous fish. The diet should include both dry foods in the form of flakes or pellets, and vegetable supplements, which are necessary for normal digestion. Periodic feeding with live or frozen foods is beneficial. It is important to avoid overfeeding and products high in fat. Feeding frequency is 1–2 times a day in small portions that the fish can consume within a few minutes.

Breeding jikin is considered a challenging task even for experienced aquarists. Spawning is paired or group, usually stimulated by an increase in water temperature. Eggs are laid on fine-leaved plants or substrate. Parents tend to eat the eggs, so they should be removed immediately after the process is complete. Fry grow slowly and require careful care and sorting, as only a small portion of the offspring inherit the ideal breed characteristics.

The fish are sensitive to water quality; the accumulation of ammonia and nitrites quickly leads to diseases. Fin infections, such as fin rot, and parasitic infestations, for example, ichthyophthiriasis, are common. Prevention includes maintaining cleanliness in the aquarium, avoiding sudden temperature fluctuations, and quarantining new specimens. Due to their selective breeding, they may be predisposed to swim bladder problems.

When purchasing, choose active fish with clean fins, free from signs of damage, film, or ulcers. A healthy jikin should have clear eyes and even breathing. It is important to consider that the breed is extremely rare, so a high price and the need for proof of origin are common factors. It is recommended to observe the fish's behavior in the store: avoid specimens that stay near the surface or lie on the bottom.