Furry Diary

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Sarasa Comet

Carassius auratus

Also called Sarasa comet goldfish, Red-and-white comet

VarietyShort profile

From Colour form of the comet goldfish; the comet type was developed in the USA in the 1880s, while the red-and-white sarasa colouring is described as originating in China, with a Japanese-derived name12

At a glance the quick version

Lifespan5 to 14 years1
Sizemedium
Bold red-and-white pattern that resembles a koi
Long, elegant forked tail
Hardy, fast swimmer that thrives in ponds
13

Looks how to spot one

Scaled fish with metallic scales and a single, long, deeply forked tail

A slim, streamlined goldfish with a single tail that is long and deeply forked, ending in pointed tips that spread like an open pair of scissors. The body is shallower than a common goldfish. The sarasa colouring is a crisp mix of bright red and clean white, often arranged in bold patches much like a red-and-white koi.132

Coloursred and white1

Personality what they are like

Lively, playful and curious. Comets like to dash back and forth and are peaceful with other fish of similar size and speed.14

Daily activity how busy a day looks

High. A quick, energetic swimmer that needs long, open swimming space; it is very much at home in a garden pond.13

Grooming and care the hands-on bits

A coldwater fish that normally needs no heater; about 16 to 21 C suits single-tailed goldfish, and pH guidance ranges from 6.0 to 8.0 (FishBase) to 7.0 to 8.4 (Aqueon). Good filtration and regular partial water changes with dechlorinated water are part of routine care.456

Home where they are happiest

Plenty of room: about 75 litres (20 US gallons) per adult is a common guideline, and FishBase gives a minimum tank length of 100 cm for the species. Fast single-tailed goldfish do especially well in a well-kept garden pond once mature, and in temperate climates they can stay outdoors all year.457

Food basics what goes in the bowl

Omnivores. Offer a goldfish-specific pellet as the staple, 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.87

Company who they like around

Sociable and peaceful with similar-sized fish; FishBase suggests groups of five or more goldfish. Best kept with other fast, single-tailed goldfish such as common goldfish, comets and shubunkins, or in a pond, rather than with slow fancy twin-tailed types.549

The story where it all began

The comet goldfish first turned up in the 1880s in the ponds of the U.S. Government Fish Commission in Washington, D.C., and Hugo Mulertt went on to breed and popularise it. The red-and-white sarasa form is described as coming from China, though its name is Japanese, and it became one of the best-loved comet colours for ponds.1

Fun facts for the dinner table

  1. 1

    The sarasa pattern looks so much like a red-and-white koi that the two are often compared side by side.1

  2. 2

    The comet is one of the few goldfish types created in the West rather than in China or Japan, and it became the most common variety in the United States.10

  3. 3

    A show comet's tail should ideally reach about three quarters of its body length.3

  4. 4

    In East Asia comets are sometimes called swallowtails because of their scissor-like tails.3

Recognised by the official bits

Goldfish Society of Great Britain (GSGB)
The comet is one of the society's standard varieties; red-and-white sarasa fish fall under the variegated metallic colouring allowed for comets2
Bristol Aquarists' Society / goldfish-types.info
Comet standard: slender body about 35% as deep as long, single deeply forked tail with pointed lobes, minimum body length 7.5 cm; metallic fish may be self-coloured or variegated3

The care rhythm Furry Diary remembers it for you

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

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Owner questions the things everyone asks

How often should I feed my Sarasa Comet?

Feed your Sarasa Comet two or three small meals daily, offering only what it can eat in two to five minutes. Furry Diary's starting plan suggests feeding once a day, but you can adjust based on your fish's appetite. Always follow the food label and consult a vet for portion guidance.87 Furry Diary plan

What does a Sarasa Comet eat, and what should it never eat?

Your Sarasa Comet enjoys a goldfish-specific pellet as its main food, plus chopped vegetables like peas or spinach and occasional treats like daphnia or brine shrimp. For foods to avoid, ask a vet or good breeder, as some items can harm goldfish.87

How much space does a Sarasa Comet need?

Each adult Sarasa Comet needs about 75 litres (20 US gallons) of water and a tank at least 100 cm long. They are active swimmers and do especially well in a well-kept garden pond once mature.457

What temperature, light or water does a Sarasa Comet need?

Keep the water between 16 and 21°C with a pH of 6.0 to 8.4, depending on your source. No heater is needed for this coldwater fish. Use good filtration and dechlorinated water. For lighting, ask a breeder or vet.456

How often should I clean a Sarasa Comet's home?

Furry Diary's plan recommends weekly 25-30% water changes, weekly glass cleaning, and monthly filter rinsing. Regular partial water changes with dechlorinated water are essential for health.6 Furry Diary plan

Can a Sarasa Comet live with others?

Yes, Sarasa Comets are sociable and peaceful with similar-sized fish. They thrive in groups of five or more with other fast single-tailed goldfish, but should not be kept with slow fancy goldfish.549

How long does a Sarasa Comet live?

With good care, a Sarasa Comet can live between 5 and 14 years.1

Can I handle a Sarasa Comet?

It is best not to handle your Sarasa Comet, as this can cause stress and injury. For specific handling advice, ask a vet or 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.

  1. Comet (goldfish) - Wikipedia en.wikipedia.orgused for origin, history, sarasa colouring, lifespan, temperament
  2. Goldfish Society of Great Britain - Varieties goldfishsociety.co.ukused for comet standard listing and variegated colouring
  3. Comet goldfish standard - goldfish-types.info (successor to the Bristol Aquarists' Society site) goldfish-types.infoused for comet standard, tail, swallowtail name
  4. Aqueon - Goldfish care sheet aqueon.comused for temperature, pH, tank volume, diet
  5. Carassius auratus - FishBase fishbase.seused for pH, tank size, group size
  6. RSPCA - Fish environment rspca.org.ukused for tank volume, water changes, filtration
  7. Goldfish - Wikipedia en.wikipedia.orgused for general goldfish care, lifespan, temperature, diet
  8. RSPCA - Fish diet rspca.org.ukused for diet and feeding routine
  9. RSPCA - Keeping fish together rspca.org.ukused for social needs
  10. List of goldfish varieties - Wikipedia en.wikipedia.orgused for variety summary
  11. VCA Animal Hospitals: Feeding times and frequency for your dog vcahospitals.comused for owner questions
  12. ASPCA: Dog grooming tips aspca.orgused for owner questions
  13. ASPCA: Cat grooming tips aspca.orgused for owner questions
  14. ASPCA: People foods to avoid feeding your pets aspca.orgused for owner questions
  15. 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.