Not furry, but we like them anyway.
Ryukin
Carassius auratus
Also called Ryūkin, Onaga (longtail), Nagasaki goldfish, Japanese ribbontail, Fringetail
From China; reached Japan via the Ryukyu Islands (present-day Okinawa), reportedly in the 1770s, and was refined there12
A friendly guide, not veterinary advice. For anything about your pet's health, ask your vet.
At a glance the quick version
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
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
The ryukin is named after the Ryukyu Islands (now Okinawa), the route by which it is said to have reached Japan.1
- 2
Old Japanese texts called it onaga, meaning 'long tail', or simply the Nagasaki goldfish.1
- 3
Its tail can grow to roughly twice the length of its body.1
- 4
A calico-coloured ryukin is known as a 'sakura', after the cherry blossom.1
- 5
Because of its tall, deep body, the ryukin is happier in a taller aquarium than most fancy goldfish.6
- 6
Breeders prize a hump that rises almost vertically behind the head.2
- 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.
- Feedingevery day
- Water changeAbout 25 to 30% of the waterevery week
- Water testevery week
- Glass cleanevery week
- Filter rinseevery month
Owner questions the things everyone asks
How often should I feed my Ryukin?
Feed your Ryukin two or three small meals each day, offering only what they can eat within two to five minutes. Furry Diary's starting plan is to feed daily. They are quick learners and will greet you at feeding time!53 Furry Diary plan
What does a Ryukin eat, and what should it never eat?
Your Ryukin is an omnivore, so offer a goldfish-specific pellet as the staple, avoid tropical flakes. Add chopped vegetables like peas or spinach, and small treats like daphnia or brine shrimp. For foods to never give, ask your vet.53
How much space does a Ryukin need?
Give your Ryukin at least 60 litres of water per fish, with a taller tank to suit their deep body. For a group, a tank at least 100 cm long is recommended. They are active swimmers and need plenty of open water.76813
What temperature, light or water does a Ryukin need?
Keep the water temperature between 10 and 21°C, with 20, 22°C ideal, and a pH of 6 to 8. A heater is usually not needed indoors. For lighting, consult a good breeder or vet.738
How often should I clean a Ryukin's home?
Clean the tank weekly with a 25, 30% water change using dechlorinated water at the same temperature. Furry Diary's plan also includes weekly glass cleaning and water testing, plus monthly filter rinsing.738 Furry Diary plan
Can a Ryukin live with others?
Ryukins are peaceful and can live alone or in groups. If keeping with others, choose slow twin-tailed fancy goldfish so everyone gets a fair share. Some sources recommend groups of five or more.938
How long does a Ryukin live?
With good care, your Ryukin can live 10 to 25 years, a wonderful long-term companion.34
Can I handle a Ryukin?
Handling is not recommended for your Ryukin. For specific advice on safe interaction, ask an exotic-pet vet or a good breeder.
Written from the sources on this page, a few checked guides (VCA, ASPCA, RSPCA) and Furry Diary's own starting care plan. A friendly guide, not a vet's advice.
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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 support@furrydiary.app and we will fix it.
- Ryukin - Wikipedia en.wikipedia.orgused for other names, origin and history, body, size, colours, sakura, hardiness
- Goldfish Society of Great Britain - Varieties goldfishsociety.co.ukused for recognition, hump and tail standard, activity of short-tailed fish
- Goldfish - Wikipedia en.wikipedia.orgused for lifespan, cognition, diet, social behaviour, temperature
- RSPCA - Fish rspca.org.ukused for lifespan up to 25 years
- RSPCA - Fish diet rspca.org.ukused for diet and feeding routine
- List of goldfish varieties - Wikipedia en.wikipedia.orgused for tall tank need, name origin
- RSPCA - Fish environment rspca.org.ukused for tank volume, temperature, water changes
- Carassius auratus - FishBase fishbase.seused for pH, aquarium size, group size, IUCN status
- RSPCA - Keeping fish together rspca.org.ukused for social needs
- Wakin - Wikipedia en.wikipedia.orgused for wakin as ancestor of ryukin
- オランダシシガシラ - Wikipedia (Japanese) ja.wikipedia.orgused for ryukin as forebear of Japanese orandas
- Tamasaba - Wikipedia en.wikipedia.orgused for related variety fun fact
- VCA Animal Hospitals: Feeding times and frequency for your dog vcahospitals.comused for owner questions
- ASPCA: Dog grooming tips aspca.orgused for owner questions
- ASPCA: Cat grooming tips aspca.orgused for owner questions
- ASPCA: People foods to avoid feeding your pets aspca.orgused for owner questions
- RSPCA: What to feed your rabbit rspca.org.ukused for owner questions
Checked 2026-09-30. Text is written in our own words from these sources.