Swims in a ball gown.
Fancy Goldfish
Carassius auratus
Also called Twin-tail goldfish, Double-tail goldfish, Fancy goldfish varieties
From China, with several varieties later refined in Japan (e.g. ranchu, ryukin, tosakin, wakin)123
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 doubled tail and anal fins in most varieties; metallic, matte or nacreous (calico) scales
Fancy goldfish are the selectively bred forms of the goldfish, usually with a short, rounded or egg-shaped body and a split, doubled tail. Depending on the variety they may have a raspberry-like head hood (wen), telescope or upward-gazing eyes, fluid-filled eye sacs, domed pearl-like scales, a high shoulder hump, or no dorsal fin at all. Scales can be shiny metallic, matte, or a mix that gives a speckled calico look.2543
Personality what they are like
Peaceful, gentle fish that move at a relaxed pace. They are sociable and will often gather together, and they quickly learn when and where food appears. Their slow swimming means they do best with other fancy varieties rather than fast single-tailed goldfish.187
Daily activity how busy a day looks
Moderate. Fancy goldfish are slower swimmers than single-tailed goldfish, so they appreciate open swimming space and gentle water flow rather than strong currents.82
Grooming and care the hands-on bits
Coldwater fish that need a filtered aquarium, never a bowl. Keep water roughly 10 to 21 C (about 20 to 22 C is often cited as ideal; orandas tolerate about 17 to 28 C), pH about 6 to 8. Change around 30% of the water each week with dechlorinated water of matching temperature. Choose smooth decorations, since hooded and bubble-eyed varieties have delicate features.915104
Home where they are happiest
Plan for at least 60 litres of water per goldfish, with a tank no smaller than about 45 x 30 x 30 cm and good mechanical and biological filtration. Goldfish bowls are not suitable because of poor oxygen exchange and unstable temperature. A heater is usually not needed.9
Food basics what goes in the bowl
Omnivores. Feed a goldfish-specific flake or pellet, not tropical food, and add chopped vegetables such as peas and spinach plus occasional thawed frozen foods, water fleas or brine shrimp. Offer small meals two or three times a day, only as much as is eaten in two to five minutes.71
Company who they like around
Goldfish are gregarious and naturally school, although a single goldfish can be kept on its own. Keep fancy twin-tailed varieties with other slow fancy types; mixing them with fast single-tailed goldfish means the fancy fish miss out on food.18
The story where it all began
The goldfish comes from a wild Chinese carp, and colour mutations were first noted during the Jin dynasty (266 to 420). By the Tang dynasty (618 to 907) people kept ornamental fish in ponds, and a golden-orange mutation became prized. Selective breeding was well established in the Song dynasty (960 to 1279), when in 1162 the empress ordered ponds for red and gold fish and yellow was reserved for the imperial family. During the Ming dynasty (1368 to 1644) goldfish began to be kept indoors in bowls, which let breeders select for delicate traits such as doubled tails, bulging eyes and head growths that would not survive in open ponds. Goldfish reached Japan in 1603 and Portugal in 1611, and from there spread across Europe, where they became a symbol of good fortune. Japanese breeders developed their own famous types, including the ranchu, ryukin and tosakin, while the oranda owes its Japanese name to Dutch traders. Goldfish arrived in North America around 1850, and today China alone recognises a few hundred breeds.1235
Fun facts for the dinner table
- 1
Goldfish have four kinds of colour-sensing cone cells, so they can see ultraviolet light as well as red, green and blue.1
- 2
Far from having a three-second memory, goldfish can remember things for at least three months and can tell shapes, colours and sounds apart.1
- 3
In Song dynasty China yellow was the imperial colour, so yellow goldfish were reserved for the imperial family.1
- 4
The ranchu is nicknamed the 'king of goldfish' in Japan, and traditional ranchu are judged from above in shallow bowls rather than through glass.3
- 5
The oranda's Japanese name, Oranda-shishi-gashira, means 'Dutch lionhead', probably a nod to Dutch traders in Japan.5
- 6
An oranda's head hood (wen) takes about one to two years to fully develop.5
- 7
Bubble eye goldfish are born with normal-looking eyes; their eye sacs start to grow at about three months old.4
- 8
Goldfish kept in darkness slowly fade until they look almost grey.1
- 9
In 1620s southern Europe, husbands traditionally gave their wives a goldfish on their first wedding anniversary as a symbol of good fortune.1
Recognised by the official bits
- IUCN Red List
- Parent species Carassius auratus assessed as Least Concern (2010)10
- Chinese goldfish fancy
- Wikipedia sources cite roughly 200 to 300 goldfish breeds recognised in China, grouped traditionally into Crucian, Wen, Dragon Eye and Egg types1
- Japanese ranchu fancy
- Ranchu are shown and judged from above in shallow bowls or vats under traditional Japanese standards3
The care rhythm Furry Diary remembers it for you
A typical home-care rhythm for a Fancy Goldfish. 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 Fancy Goldfish?
Feed your Fancy Goldfish small meals two or three times a day, only as much as they can eat in two to five minutes. Furry Diary's starting plan suggests feeding once daily, but you can adjust based on your fish's needs. Always follow the food label and ask your vet for specific amounts.71 Furry Diary plan
What does a Fancy Goldfish eat, and what should it never eat?
They are omnivores and do best with goldfish-specific flakes or pellets, plus chopped vegetables like peas and spinach and occasional thawed frozen foods. Never feed them tropical fish food, and avoid overfeeding to keep their water clean.71
How much space does a Fancy Goldfish need?
Plan for at least 60 litres of water per goldfish, with a tank no smaller than about 45 x 30 x 30 cm. Goldfish bowls are not suitable because of poor oxygen exchange and unstable temperature.9
What temperature, light or water does a Fancy Goldfish need?
Keep the water between 10 and 21°C, with about 20 to 22°C often ideal, and a pH of 6 to 8. A heater is usually not needed, and use gentle water flow with good filtration. Change around 30% of the water weekly with dechlorinated water at matching temperature.915104
How often should I clean a Fancy Goldfish's home?
Change about 25 to 30% of the water each week, as Furry Diary's starting plan suggests. Also test the water weekly, clean the glass, and rinse the filter monthly. Always use dechlorinated water at matching temperature.91 Furry Diary plan
Can a Fancy Goldfish live with others?
Yes, they are sociable and do best with other slow fancy goldfish varieties. Avoid mixing them with fast single-tailed goldfish, as the fancy fish may miss out on food. A single goldfish can also be kept on its own.18
How long does a Fancy Goldfish live?
With good care, they can live between 10 and 25 years. Their lifespan depends on water quality, diet, and tank size, so a proper setup is key.16
Can I handle a Fancy Goldfish?
It's best not to handle them, as their delicate features like hoods or bubble eyes can be easily injured. Always use a soft net if you need to move them, and keep handling to a minimum.94
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.
- Goldfish - Wikipedia en.wikipedia.orgused for history, lifespan, temperature, vision, memory, behaviour, colours
- List of goldfish varieties - Wikipedia en.wikipedia.orgused for varieties, body types, origin of Japanese varieties, breed counts
- Ranchu - Wikipedia en.wikipedia.orgused for size, Japanese history and judging tradition
- Bubble eye - Wikipedia en.wikipedia.orgused for size, eye sac development
- Oranda - Wikipedia en.wikipedia.orgused for size, colours, temperature tolerance, name origin, wen
- Fish - RSPCA rspca.org.ukused for lifespan and size of goldfish
- Fish diet - RSPCA rspca.org.ukused for diet and feeding routine
- Fish company - RSPCA rspca.org.ukused for social needs and mixing twin- and single-tailed goldfish
- Fish environment - RSPCA rspca.org.ukused for tank volume, temperature, filtration, water changes
- Carassius auratus - FishBase fishbase.seused for scientific name, pH, IUCN status, native range
- 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.