Sarasa Comet Goldfish (Carassius auratus)

Pick a red-and-white comet for the garden pond

The Sarasa Comet Goldfish is the red-and-white form of the comet, a slim, single-tailed goldfish (Carassius auratus) with a long, deeply forked tail. Its pearly white body is broken by bold red-orange patches across the back, head and tail root, and the fins are streaked red and white. In a garden pond a group of sarasa comets stands out clearly from the patio, and because no two fish carry the same pattern, each one is easy to recognise. Sarasa comets are hardy, fast and long-lived, and they stay outdoors all year in a well-kept pond.

The name joins two traditions. Wikipedia's comet goldfish article, drawing on Johnson and Hess's Fancy Goldfish and Chris Andrews's guide, records that the comet was developed in the United States from the common goldfish by Hugo Mulertt in the 1880s and first appeared in the ponds of the US Fish Commission in Washington, DC. "Sarasa" is a Japanese word, and the red-on-white pattern is often compared with the Kohaku pattern of koi. The goldfish itself comes from East Asia: FishBase places its native range there, in still or slow-flowing rivers, lakes, ponds and ditches.

Read the tail and the pattern

Practical Fishkeeping defines a comet by its tail rather than its colour: any goldfish with the comet tail counts, and a good tail is forked and well spread, without drooping or overlapping lobes.

Compare it with our Bronzed Comet Goldfish, the same comet shape in metallic bronze, or read our comet goldfish guide for a side-by-side look at comets and fancy goldfish. The full range of single-tailed and fancy goldfish is in our goldfish category.

Choose the size that suits your pond

One purchase supplies one live Sarasa Comet Goldfish in the size you pick. All four sizes are young fish; even the largest has a long way to grow.

Match the size to the job

Sex is not chosen or guaranteed. The red and white pattern on each fish is unique, so the photographs show the colour form, not the individual you will receive. The Maidenhead Aquatics fish database recommends keeping goldfish in groups and says mixed varieties are fine, so several sarasa comets, or sarasas alongside other single-tailed goldfish, make a better pond than one fish on its own. Our delivery page explains dispatch days and the Live Arrival Guarantee.

Plan space for a 30 cm adult

A 2–3 in sarasa will not stay small. OATA gives the most common maximum body length of pond goldfish as up to 30 cm; Practical Fishkeeping gives up to 35 cm for comets, which regularly reach 30 cm; and the Maidenhead Aquatics database gives 30 cm or more for sarasa comets. FishBase records a maximum of 48 cm total length for the species. Lifespan figures vary more: OATA cites reports of goldfish living up to 20 years, the Maidenhead Aquatics database says more than twenty years, Wikipedia gives 5–14 years and longer in good conditions, and FishBase records a reported age of 41 years. Whichever figure you take, a sarasa comet is a long-term commitment.

Run a three-step pond check

1. Depth: OATA advises fish ponds at least 45–60 cm deep; the Maidenhead Aquatics database asks for at least 60 cm in places.
2. Volume: work out the litres with our tank volume calculator. OATA says goldfish suit most smaller pond systems, while koi, tench and orfe need 4,500 litres or more.
3. Stock: the Maidenhead Aquatics pond guide suggests 25 cm of fish per 455 litres, counting adult size. A pond of 2,275 litres therefore holds about 125 cm of fish, or four adult comets at 30 cm. Our stocking calculator helps with mixed stock.

Indoors, a comet needs a very large aquarium. OATA's goldfish aquarium sheet asks for at least 100 litres for one adult goldfish plus 50 litres for each extra adult, and Practical Fishkeeping recommends a tank at least 120 cm long, with 150–180 cm better in the long run. That is why both treat comets as pond fish first.

Lay out the pond in zones

OATA explains that depth gives more stable temperatures, with a cool zone at the bottom in warm spells and a warmer area in freezing weather. The pond should get some sun to help plants grow and warm the water in spring and summer, but too much drives temperature swings and algae; the OATA garden pond guide suggests about four to six hours of sun a day with some shade, away from overhanging trees. The Maidenhead Aquatics pond guide aims for roughly 33–50% of the surface covered with plants.

Divide the pond by function

Hold the water in the comet range

Comets are tolerant, but the sources give different ranges, so compare them before you set targets.

The pH that suits all four is 7.5–8.0, in moderately hard water, with 10–20°C as the comfortable band for active fish. More important than any single figure are the waste readings OATA sets: ammonia and nitrite at zero and nitrate no more than 20 mg/l above your tap water.

Treat every top-up

Treat all new tap water with a conditioner to remove chlorine or chloramine, as OATA advises; conditioners and test kits are in our water care and treatment range. Check your water company's postcode report for hardness and pH, compare it with this page in our water matcher, and use the water chemistry guide if any of the terms are new.

Filter the pond and care for it through the seasons

OATA says any pond that holds fish needs a filter, and a pump or fountain helps to circulate and oxygenate the water; Practical Fishkeeping notes that goldfish are messy, especially when large. A new pond needs time: the OATA garden pond guide asks for dechlorinated water and running equipment for at least 24 hours before any fish go in, and says a fishless cycle with ammonia takes several weeks. Add fish a few at a time so the filter bacteria can keep up and you avoid the new pond syndrome OATA warns about. Our nitrogen cycle guide explains why.

Follow a seasonal routine

OATA also suggests replacing a UV bulb about once a year.

Feed a measured meal by temperature

Practical Fishkeeping notes that wild-type goldfish eat insects and their larvae, other aquatic invertebrates, plants and detritus, and that comets take a wide range of dried and frozen foods. OATA advises feeding once a day only what the fish can eat within a few minutes, with higher-protein food in summer and a lower-protein wheatgerm food as the water cools. The Maidenhead Aquatics database gives the same advice for sarasa comets in late autumn.

Build one measured meal

• Summer staple: a floating food such as Tropical Pond Sticks Mixed or Tropical Pond Pellet Mix.
• Cooler water: Tropical Koi & Goldfish Wheat Germ & Garlic.
• Occasional extra: thawed Koi and Goldfish Special frozen food in the warm months.
• Portion: what disappears within a few minutes; net out anything left.
• Cold water: OATA says it may be better not to feed below 8°C; the Maidenhead Aquatics pond guide gives wheatgerm only at around 10°C and normal food once the water stays above 10–15°C.

More foods are in our fish food range.

Introduce new comets calmly

Add new fish between spring and early autumn: the OATA garden pond guide advises against adding fish in winter. Make sure ammonia and nitrite read zero, keep the bag out of bright light, float it for 10 minutes, then add small amounts of pond water before releasing the fish with as little bag water as possible, as OATA describes. Our guide on how to acclimatise new fish covers the steps in more detail.

Use a first-week checkpoint plan

Keep comets with fish that match their pace

Comets are quick, single-tailed swimmers. OATA advises against keeping them with fancy goldfish, because comets swim faster and often take the food first, and some boisterous fish have been reported nipping the fins of fancies; Practical Fishkeeping gives the same warning about twin-tailed goldfish. On the other hand, the Maidenhead Aquatics database calls the sarasa comet a good match for koi and says it complements shubunkins and yellow goldfish, and OATA notes that most pond fish get on with each other.

Screen each companion

Our tank mates tool helps check a mix, and the whole coldwater range is in goldfish and coldwater fish.

Spot health problems early

OATA's checklist for a healthy pond fish is clear, bright eyes, undamaged fins, intact scales with no ulcers or bumps, normal swimming and steady breathing. Practical Fishkeeping adds a specific warning for comets: avoid fish with visible blood in the fins, which can point to poor water or poor health. The white parts of a sarasa make red streaks easy to see, so look closely at the tail.

Pair each sign with an action

OATA warns that the immune system can be weak after the cold months, so be especially watchful as the water warms in spring.

Expect spawning in spring

Goldfish are the pond fish most likely to breed. The Maidenhead Aquatics database says males begin spawning chases at 15°C and above, the eggs are laid among plants or on spawning mops, and they hatch in 48–72 hours depending on temperature. OATA suggests a shallow, heavily planted area to give fry a chance, because adult goldfish eat both eggs and fry. Keep females from being outnumbered by males, as the database advises, so the chasing is shared out.

Know what the young will look like

Young goldfish start out brown, and the Maidenhead Aquatics database says bright colour can take up to a year to appear, with many youngsters reverting to standard goldfish colour. Practical Fishkeeping notes that comets cross freely with common goldfish and shubunkins, and that without selection the offspring drift back towards the olive-green wild type. To sex adults, Practical Fishkeeping describes males developing white breeding tubercles on the gill covers and ridges on the pectoral fins, while females become plump with eggs and look lopsided from above.

Rehome, never release

No licence is needed to keep goldfish in England and Wales, according to government guidance. Releasing them is another matter: OATA says it is illegal and often fatal for the fish, and FishBase lists the goldfish as a potential pest that has harmed habitats where it has been introduced. Pass surplus fish to another pond keeper or a local aquatic shop.

Answer Sarasa Comet Goldfish buying questions

What is a Sarasa Comet Goldfish?

It is the red-and-white form of the comet goldfish, Carassius auratus: a slim, single-tailed goldfish with a long, deeply forked tail and red-orange patches on a white body. It is a hardy pond fish.

How big do sarasa comets grow?

Usually to about 30 cm. OATA gives up to 30 cm as the most common maximum for pond goldfish, Practical Fishkeeping says comets grow to 35 cm and regularly reach 30 cm, and the Maidenhead Aquatics database gives 30 cm or more.

Can a sarasa comet live outside all year?

Yes, in a filtered pond at least 45–60 cm deep. Keep part of the surface free of ice in winter and reduce or stop feeding when the water is cold.

Can I keep a sarasa comet in an aquarium?

Only a very large one. OATA asks for at least 100 litres for one adult goldfish plus 50 litres for each extra adult, and Practical Fishkeeping recommends a tank of at least 120 cm, ideally 150–180 cm. A pond suits it better.

Can sarasa comets live with fancy goldfish?

It is better not to. OATA and Practical Fishkeeping both advise keeping comets apart from twin-tailed fancy goldfish, which are slower and lose out at feeding time.

Can sarasa comets live with koi?

Yes, in a large enough pond. The Maidenhead Aquatics database describes the sarasa comet as a good match for koi.

How many sarasa comets should I keep?

The Maidenhead Aquatics database recommends keeping goldfish in groups, and varieties can be mixed. Work the number out from adult size: about 25 cm of adult fish per 455 litres, so four adults need around 2,275 litres.

How many fish come with one purchase?

One live Sarasa Comet in the size you choose: 2–3 in, 3–4 in, 4–5 in or 5–6 in. Sex is not chosen or guaranteed, and every fish has its own pattern.

Consult the care references

• Practical Fishkeeping: Comet goldfish — what makes a comet, sarasa colouring, adult size, pond and aquarium space, water, diet, companions and sexing.
• Maidenhead Aquatics fish database (fishkeeper.co.uk): Sarasa Comet — sarasa comet size, temperature, pH, pond depth, companions, colour development, spawning and lifespan.
• OATA: How to look after pond fish — UK guidance on pond fish water values, sizes, group sizes, pond volume and depth, seasonal feeding, winter care, health signs and breeding.
• OATA: How to set up and look after your garden pond — UK guidance on siting, building, maturing and stocking a garden pond, adding fish and keeping herons and otters out.
• OATA: How to look after goldfish in an aquarium — UK guidance on goldfish in aquariums: volume per fish, water values, weekly maintenance and keeping comets apart from fancy goldfish.
• Maidenhead Aquatics: Taking care of goldfish in a pond — pond stocking rule, filter cleaning, seasonal feeding temperatures, oxygen and plant cover for goldfish ponds.
• FishBase: Carassius auratus — native range, maximum length and age, water values, wild diet and the pest risk when goldfish are released.
• Wikipedia: Comet (goldfish) — history of the comet goldfish, its body and tail, colour forms including the sarasa, and lifespan (citing Johnson & Hess and Andrews).
• GOV.UK: Introduce or keep non-native fish — England and Wales guidance listing goldfish and ide or orfe among the non-native fish you can keep without a licence.
• Tropical Fish Co delivery policy — current dispatch days and Live Arrival Guarantee terms.