Nankin

The nankin is a rare selectively bred goldfish variety from Japan. Its main features are the complete absence of a dorsal fin and a compact, egg-shaped body. The head is small and lacks the growths seen in many other breeds. The tail fin is forked and short; from above, the body often looks triangular. The traditional colouration combines white and red, with individuals showing a balanced distribution of these colours being most prized.

This variety does not exist in nature and is entirely an artificially developed ornamental form. The breed was established historically in the Izumo region (Shimane Prefecture, Japan) in the mid-18th century. In the aquarium, these fish need a stable environment typical of ornamental goldfish, with clean water and no strong current.

The nankin has a calm, sluggish temperament. Because of its body shape and the absence of a dorsal fin, it is a rather weak swimmer. It is best kept in a species tank or with other slow-moving goldfish breeds. Fast, active species may outcompete it for food or damage it.

An adult fish needs an aquarium of at least 75 litres, though larger tanks are preferable. Effective filtration and regular water changes are important, as this breed is sensitive to water quality. Avoid sharp objects and decorations that could damage the fins or body. Lighting should be moderate.

The fish are omnivorous and undemanding about food. The diet should be balanced, combining quality dry pellets with vegetable supplements or frozen foods. Control portion sizes to prevent overfeeding and water fouling. Feed once or twice a day in small amounts.

Breeding nankin is considered difficult and demands experience. Spawning is triggered by raising the water temperature in spring. The fish lay eggs on fine-leaved plants or special substrates. Fry need careful attention, regular sorting, and quality starter food to develop the body shape characteristic of the breed.

The variety is susceptible to the diseases typical of goldfish, including bacterial infections and parasitic infestations, often caused by poor water quality or stress. Because of the absent dorsal fin and body shape, fish may be prone to swim bladder disorders. Prevention consists of maintaining clean water and stable parameters.

When buying, choose active fish with clean fins and no visible damage on the body. Pay attention to body symmetry and the absence of signs of emaciation or disease, such as white spots or coating. Given the rarity of the breed, it is best purchased from specialist breeders, as nankin is very rarely found in general trade.