Ryukin Goldfish

Color varieties: The Ryukin Goldfish come in deep-red, red-and-white, red-and-black, red-white-black, white, iron, blue, greenish, chocolate, and calico varieties. The calico colored Ryukin Goldfish usually has a much smaller hump. The Tetsu Onaga is a rare iron-colored variety. They have very round bodies, a fat belly, and a wider caudal fin than the Fantail Goldfish. They may be long-finned or short-finned and the dorsal fin is high. The caudal fin may be twice as long as the body and may have three or four lobes. They have evenly paired anal, ventral, and pectoral fins.

A long-tailed version of the Ryukin Goldfish known as Fringetail or Ribbontail Ryukin is also available. Two more variants, the Yamagata Kingyo or Yamagata Goldfish and Tetsu Onaga or Iron-colored Longtail are also available. The Yamagata Goldfish also known as Sabao or Mackerel Tail or Tamasaba is a hardy single tailed Ryukin Goldfish that has been developed in Yamagata in Northern Japan. There is a Globe Eye version of the Ryukin Goldfish which has protruding eyes in addition to all the characteristics of the Ryukin Goldfish.

Size: up to 10 inches

Gender: It is impossible to determine the sex of Goldfish when they are young. They become sexually mature at 1 year of age and the male is usually smaller and more slender than the female. In the breeding season, the male also has white prickles or ‘breeding tubercles’ on the gill covers and head.

Aquarium maintenance

Lifespan: up to 30 years

Temperature: 65 - 75°F

pH balance: 6.5 - 7.5

Aquarium specifications: 

These Goldfish are best housed in a 30-gallon tank. Ryukin Goldfish that are kept in a fish bowl have stunted growth (due to the high nitrate level) and a reduced lifespan. The Ryukin Goldfish produce a lot of waste products like ammonia and therefore never thrive in a small or crowded aquarium. Soft and silky cold-water plants grafted onto rocks or wood (e.g. Anubias, Java Fern, Anacharis, etc.) are good choices. Natural leaves that are pointed, or even plastic plants may hurt these delicate fish. The preferred substrate is fine and smooth sand which will pose little danger when the fish tends to swallow the particles. They prefer tanks with little or no current.

Ryukin Goldfish require optimum water conditions. They require very well-aerated water and an efficently filtered tank.

Water hardness: 28.57 - 142.85 mg/L

Behavior

Temperament: 

The Ryukin Goldfish is a very hardy fish and can be selected as a beginner fish. It is a very active fish and though it can live with other species of Goldfish, it is not compatible with weaker species such as the Telescope Goldfish and Bubble Eye Goldfish, which could be bullied by the stronger Ryukin Goldfish. Lionhead Goldfish, Oranda Goldfish, and Ranchu Goldfish are more appropriate as companions since they are more gregarious by nature.