Furry Diary

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Ryukin

Carassius auratus

Also called Ryūkin, Onaga (longtail), Nagasaki goldfish, Japanese ribbontail, Fringetail

VarietyDeep profile

From China; reached Japan via the Ryukyu Islands (present-day Okinawa), reportedly in the 1770s, and was refined there12

At a glance the quick version

Length21 to 25 cm1
Lifespan10 to 25 years34
Sizemedium
Hardy and attractive fancy goldfish
Eye-catching high-backed profile
Lively swimmer, especially the short-tailed form
12

Looks how to spot one

Scaled fish with a short, deep body, a high shoulder hump, tall dorsal fin and divided triple or quadruple tail

The ryukin is a short, very deep-bodied twin-tailed goldfish with a fairly pointed head. Its signature feature is the back, which climbs steeply just behind the head to form a hump; the steeper and closer to upright, the more breeders like it. It carries a tall dorsal fin, and its three- or four-lobed tail can be short and neat or long and flowing, sometimes close to twice the length of the body.12

Coloursdeep redorangered and whitewhitesilverblueblacklavender greyironcalico (sakura)1

Personality what they are like

A peaceful, sociable goldfish that mixes happily with other fancy varieties. Ryukins are among the more active twin-tails, and like all goldfish they quickly learn feeding times and come to the front to greet their keeper.235

Daily activity how busy a day looks

Moderate to fairly high for a fancy goldfish. Short-tailed ryukins in particular are energetic swimmers, so give them plenty of open water. Their tall body shape means a deeper tank suits them better than a shallow one.26

Grooming and care the hands-on bits

Keep in a filtered aquarium or pond with weekly partial water changes of about 30%, using dechlorinated water at the same temperature. General goldfish guidance gives a water temperature of 10 to 21 C, with 20 to 22 C often cited as ideal, and a pH of about 6 to 8. A heater is not normally needed indoors.738

Home where they are happiest

Allow at least 60 litres of water per goldfish, with more being better, and choose a taller tank than for most fancy goldfish to suit the ryukin's deep body. FishBase suggests a tank at least 100 cm long for a group. Ryukins also do well in large commercial ponds, where some grow to their full size. Good filtration and a wide water surface are important.76813

Food basics what goes in the bowl

Omnivores. Offer a goldfish-specific pellet as the staple (not tropical flakes), which suits their need for less protein and more carbohydrate than many fish foods. Add chopped vegetables such as peas or spinach, and small amounts of daphnia or brine shrimp as treats. Feed two or three small meals a day, giving only what is eaten within two to five minutes, because goldfish will keep eating if food is offered.53

Company who they like around

Sources differ. The RSPCA notes goldfish can live alone, while other sources describe them as sociable fish that shoal, and FishBase suggests aquarium groups of five or more. They are very peaceful with each other. Keep them with other slow, twin-tailed fancy goldfish rather than fast single-tailed types, so everyone gets a fair share at feeding time.938

The story where it all began

The ryukin is Chinese in origin and is thought to have arisen as a mutation of the wakin, the double-tailed goldfish from which many fancy varieties descend. Its name points to its route into Japan: it is said to have arrived through the Ryukyu Islands, today's Okinawa Prefecture, reportedly around the 1770s, with written references from 1833. Early Japanese writings called it onaga, meaning long tail, or the Nagasaki goldfish, while English books used names such as Japanese ribbontail and fringetail. Japanese breeders went on to use the ryukin in other varieties; for example the oranda's Japanese line is described as longer-bodied than its ryukin forebears. Today the ryukin is one of the standard varieties listed by the Goldfish Society of Great Britain.110112

Fun facts for the dinner table

  1. 1

    The ryukin is named after the Ryukyu Islands (now Okinawa), the route by which it is said to have reached Japan.1

  2. 2

    Old Japanese texts called it onaga, meaning 'long tail', or simply the Nagasaki goldfish.1

  3. 3

    Its tail can grow to roughly twice the length of its body.1

  4. 4

    A calico-coloured ryukin is known as a 'sakura', after the cherry blossom.1

  5. 5

    Because of its tall, deep body, the ryukin is happier in a taller aquarium than most fancy goldfish.6

  6. 6

    Breeders prize a hump that rises almost vertically behind the head.2

  7. 7

    The tamasaba from Yamagata Prefecture has a ryukin-like body but a long single tail.12

Recognised by the official bits

Goldfish Society of Great Britain (GSGB)
Listed among the society's standard fancy goldfish varieties, with a standard describing the shoulder hump and tail2
IUCN Red List
Parent species Carassius auratus assessed as Least Concern (2010)8

The care rhythm Furry Diary remembers it for you

A typical home-care rhythm for a Ryukin. It is our own starting plan, not a vet's advice, and you can change every line in the app.

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Where this comes from

Every breed page shows where each fact comes from. If we got something wrong, sorry, we are pet people, not a science magazine. Tell us at [email protected] and we will fix it.

  1. Ryukin - Wikipedia en.wikipedia.orgused for other names, origin and history, body, size, colours, sakura, hardiness
  2. Goldfish Society of Great Britain - Varieties goldfishsociety.co.ukused for recognition, hump and tail standard, activity of short-tailed fish
  3. Goldfish - Wikipedia en.wikipedia.orgused for lifespan, cognition, diet, social behaviour, temperature
  4. RSPCA - Fish rspca.org.ukused for lifespan up to 25 years
  5. RSPCA - Fish diet rspca.org.ukused for diet and feeding routine
  6. List of goldfish varieties - Wikipedia en.wikipedia.orgused for tall tank need, name origin
  7. RSPCA - Fish environment rspca.org.ukused for tank volume, temperature, water changes
  8. Carassius auratus - FishBase fishbase.seused for pH, aquarium size, group size, IUCN status
  9. RSPCA - Keeping fish together rspca.org.ukused for social needs
  10. Wakin - Wikipedia en.wikipedia.orgused for wakin as ancestor of ryukin
  11. オランダシシガシラ - Wikipedia (Japanese) ja.wikipedia.orgused for ryukin as forebear of Japanese orandas
  12. Tamasaba - Wikipedia en.wikipedia.orgused for related variety fun fact

Checked 2026-09-30. Text is written in our own words from these sources.