Ryukin goldfish (Carassius auratus)

Welcome to our comprehensive guide to the Ryukin goldfish, a stunning and distinctive variety of the Carassius auratus species. In this article, we’ll explore everything you need to know about the Ryukin, from its unique appearance to its care requirements. Whether you’re a seasoned goldfish enthusiast or a beginner looking to add a new member to your aquatic family, read on to discover why the Ryukin is a beloved favorite among fishkeepers worldwide.

Size and appearance

The Ryukin is a short, deep-bodied fancy goldfish characterized by its prominent hump in the shoulder region. On average, they typically grow to around 15-20 centimeters (6-8 inches) in length, although some specimens may reach even larger sizes. Their stunning coloration ranges from vibrant reds, oranges, and yellows to calico patterns, making them a striking addition to any aquarium.


Originating from Asia, particularly Japan, the Ryukin goldfish is named after the Ryukyu Islands where it was first selectively bred. Today, they are popular among aquarists worldwide and can be found in freshwater aquariums all over the globe.


Ryukin goldfish are known for their playful and active behavior, often seen darting around the aquarium and exploring their surroundings. While they are generally peaceful, they may exhibit some aggression during feeding times or when establishing dominance within a group of fish.


Like other varieties of goldfish, Ryukins are omnivorous and enjoy a varied diet. They thrive on a combination of high-quality flake or pellet foods supplemented with fresh vegetables such as peas, lettuce, and zucchini. Additionally, occasional treats like bloodworms or brine shrimp can provide additional nutrients and enrichment. However, our advice is to feed them with anything that sinks to the bottom, because when they eat floating flakes from the water surface, they also ingest a lot of air (gas), which can lead to them flipping over and swimming abnormally. Another tip we have is to soak granules in water before feeding them to your goldfish, so they won’t expand in the fish’s stomach, which prevents problems with the digestive system.

How to keep the Ryukin goldfish at home

To keep Ryukin goldfish happy and healthy in your home aquarium, it’s essential to provide them with adequate space and filtration. A tank size of at least 75-100 liters (20-30 gallons) is recommended for a single Ryukin, with an additional 40-50 liters (10-15 gallons) per additional fish.

Water parameters: Maintaining stable water parameters is crucial for their well-being. Many aquarists know that you can keep goldfish in a cold water aquarium, without extra heating, but in recent years we experienced that goldfish from Asia feel much better when kept in warmer water. They are healthier, get less sick and grow and develop better than when they are in colder water. That’s why we recommend to keep them at a water temperature between 26-28 °C (78-82 °F) and maintain a pH level between 6.5-7.5. Regular water changes and proper filtration are essential to keep the water clean and free of toxins.
Conditions: While Ryukins are generally hardy fish, they can be susceptible to certain diseases such as fin rot or swim bladder issues if water quality is not adequately maintained. Ensure a balanced diet, regular monitoring of water parameters, and a stress-free environment to minimize the risk of health issues.

In conclusion, the Ryukin goldfish is a beautiful and captivating addition to any freshwater aquarium. With proper care and attention, these stunning fish can provide years of enjoyment and companionship for fishkeepers of all experience levels. Whether you’re a seasoned aquarist or a beginner, consider adding a Ryukin to your aquatic family and experience the joy of owning one of the most beloved fancy goldfish varieties.

Scientific nameCarassius auratus
Type of aquariumFreshwater
Size15-20 centimeters (6-8 inches)
RegionAsia, particularly Japan
Ideal tank size75-100 liters (20-30 gallons) for one fish
Ideal water temperature26-28 °C (75-82 °F)
DietHigh-quality flakes or pellets, supplemented with fresh vegetables and occasional treats
ReproductionEgg layers, external fertilization
Life span10-15 years
SchoolingNot a schooling fish

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