Nankin

Nankin key facts

Care level

Advanced

Lifespan

10-15 years

Size

10-15cm

Temperature

15〜25℃

Diet

Goldfish pellets

Tank

Shallow top-viewing container ideal

Temperature

15-25°C

Conservation

Obtain through conservation societies

Coloring

Red confined to head is ideal

Notes

Extremely difficult to obtain. Participation in conservation encouraged

About Nankin

Nankin is a uniquely Japanese goldfish originating from the Izumo region of Shimane Prefecture and holds the distinction of being designated a national natural monument. Its history is said to trace back to the Edo period, with local preservation societies dedicating generations of effort to maintaining the breed's purity. The most striking feature is the bold contrast between its rounded, pure white body and vivid red head, while its dorsal-fin-free silhouette lends it a quiet, dignified presence unlike any other goldfish. Nankin swim slowly and prefer the lower areas of the tank, projecting a calm character that brings a natural sense of tranquility to any room. The appeal of keeping Nankin lies not only in their rarity but also in the deep bond that forms over a lifespan of 10 to 15 years. Though not easy to obtain, the experience of living alongside a Nankin is genuinely singular and deeply rewarding.

7 things to know before welcoming a Nankin

1. 1A Rare National Monument

   Nanjing is designated as a National Natural Monument, making it extremely limited in circulation. Acquiring one typically requires going through specialist breeders or conservation society channels in the Izumo region. Always verify a trustworthy source before purchasing.

2. 2Provide Ample Space

   Adults grow to 10–15 cm, so plan for at least 30–40 liters of water per fish. Their rounded body shape makes them less agile swimmers, so gentle water flow is essential. Avoid overcrowding, as it degrades water quality and can cause health problems.

3. 3Temperature and Water Quality

   Nanjing thrive at around 15–25°C and are sensitive to sudden temperature changes. Maintain stable water quality with a filtration system and perform partial water changes (about one-third) roughly once a week. Regular use of a water test kit to monitor ammonia and nitrite levels is recommended.

4. 4Gentle and Calm Temperament

   Nanjing are relatively calm and can coexist with other goldfish, but they may lose out on food to faster-swimming varieties. Ideal tank mates are goldfish of similar size and swimming ability. Providing a peaceful environment will allow them to thrive as ornamental fish.

5. 5Diet and Feeding Tips

   A quality sinking or floating goldfish pellet formula serves as the staple diet. Due to their rounded body, the digestive system can be stressed easily, and overfeeding raises the risk of swim bladder disorder. Feed once or twice daily in amounts eaten within 2–3 minutes, and promptly remove any uneaten food.

6. 6Watch for Swim Bladder Issues

   Goldfish with round body shapes like the Nanjing are prone to swim bladder disorder, which affects buoyancy. Cold water temperatures, indigestion, and overeating are common triggers. Maintaining stable water temperature and feeding appropriate amounts are the key preventive measures.

7. 7Long-Term Care and Costs

   With a lifespan of 10–15 years, Nanjing require a long-term commitment. Initial costs include a tank, filter, heater, and other equipment. As a National Natural Monument breed, individual fish prices can be higher than common goldfish varieties. Plan ahead by factoring in setup costs, ongoing maintenance, and purchase price before getting started.

Frequently asked questions about Nankin

Q.Where can I buy a Nankin goldfish?

A.Nankin are rarely found in general pet shops. The main sources are preservation societies in the Izumo region, specialist breeders, and dedicated goldfish retailers. In recent years, it has also become possible to find them through online live-fish marketplaces.

Q.Can beginners keep Nankin goldfish?

A.Keeping Nankin is manageable with a basic knowledge of goldfish care, but given their rarity and higher purchase cost, it is advisable to set up your environment and gain some experience before taking the plunge. Getting comfortable with water quality management beforehand will give you a much stronger foundation.

Q.How many Nankin can be kept together?

A.As a general guideline, two to three Nankin in a standard 60 cm tank (approximately 60 liters) is considered appropriate. Since adults can reach 10 to 15 cm, it is important to ensure sufficient space and avoid overcrowding.

Q.How does the red coloration on Nankin's head change over time?

A.Juvenile Nankin are often predominantly reddish, and the distinctive white body with red head pattern gradually emerges as they mature. There is individual variation in how the coloration develops, and factors such as water quality, lighting, and diet are also believed to influence the final appearance.

Q.Can Nankin tolerate cold water temperatures in winter?

A.Nankin are adapted to Japan's climate and can tolerate moderately cool water. However, sudden drops in temperature can cause illness, so it is important to prevent rapid fluctuations during winter. For indoor setups, using a heater to maintain a stable temperature of around 15°C is a safe and reliable approach.

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