Red Cap Fantail Goldfish (Carassius auratus)

Choose a red cap fantail goldfish

The Red Cap Fantail is a red cap fantail goldfish: a fantail form of Carassius auratus with a white body and white fins, crowned with a single patch of red on top of the head. Underneath the colour it is a classic fantail, with a short, rounded body and a divided, forked double tail carried high behind it.

Fantails are among the hardiest of the twin-tailed fancy goldfish. A UK breeder quoted by the Bristol Aquarists’ Society describes them as hardy and long-lived, and among the easier twin-tails to breed. Red and white goldfish have a long history too: the society dates the first white and red-and-white goldfish to domestic ponds in China during the Southern Song dynasty (1127–1279).

Tell a red cap fantail from a redcap oranda

So although both fish are white with red heads, they are different varieties, and the difference matters when you compare prices or pictures. Practical Fishkeeping’s fantail breeder lists a hood developing on the head, like a ranchu or oranda, among the faults of an English fantail. If you want the hooded type, our Red Oranda shows what an oranda’s head growth looks like.

Know what one purchase supplies

Each purchase is one live Red Cap Fantail of about 3–4 cm. That is a young fish: the UK fantail standard sets a minimum body length of 5.5 cm before a fish is judged, so the body, tail and head markings are still developing. Sex is not specified; OATA notes that mature males grow small white tubercles on the gill covers and pectoral fins in spring and summer, and females are deeper-bodied, but these signs come with maturity.

The photographs show the colour form and are based on a reference picture. They are not photographs of the fish you will receive, and the reference image shows a more developed fish than a 3–4 cm youngster.

Expect each red cap to be different

The Bristol Aquarists’ Society explains that white areas on a goldfish carry no pigment cells, while red areas are rich in red pigment cells. On a red cap fantail the size, shape and depth of the red patch vary from fish to fish, and a young goldfish can still change as it grows. Light is the main outside influence on colour, the society says: dim conditions give a pale fish, good lighting a saturated one. Diet has a smaller effect. We cannot guarantee how the cap will look on the adult fish.

Give the fantail room to grow

A fantail bought at 3–4 cm grows into a deep-bodied adult of up to about 20 cm, OATA’s figure for fancy goldfish. Plan the aquarium for that adult, not for the youngster in the bag. OATA asks for at least 100 litres for the first adult and 50 litres for every additional adult. The RSPCA gives at least 60 litres per goldfish, works on 2 litres for every 0.5 cm of fish, and rules out bowls and small decorative tanks.

Turn the guidance into a tank size

• One adult fantail: at least 100 litres by OATA’s rule.
• Two adults: at least 150 litres.
• Three adults: at least 200 litres. Practical Fishkeeping suggests 120 × 60 cm of floor space for three adult telescopes and says fantails can share that tank, which gives a useful footprint to aim for.

Measure your aquarium and convert it to litres with our tank volume calculator. Choose length and width over height: the RSPCA notes that wide tanks exchange oxygen better than tall, narrow ones.

Furnish to protect the fins

A fantail’s tail is shorter than a veiltail’s but still easily torn. OATA warns against decor with sharp or rough edges, which can damage long fins, and recommends aquarium gravel or sand. Live plants are ideal, OATA says, though goldfish may eat delicate ones; plastic plants and ornaments such as pots or caves give shelter where live plants are not used.

Check every item before it goes in

1. Run a finger along every rock, ornament and piece of wood; anything that snags skin will snag fins.
2. Pick small, round gravel or sand that a goldfish can sift without injury.
3. Choose tough plants such as Anubias, or soft plastic plants with no sharp tips.
4. Leave an open area at the front for swimming and feeding.
5. Place the tank away from direct sunlight, radiators and draughts, and light it from above for a regular day and night.

Hold fancy goldfish water values

Goldfish need cool, clean, well-oxygenated water rather than heat. OATA’s values below are written for fancy goldfish; FishBase gives the species a pH of 6.0–8.0 and hardness of 5–19 dH, and the RSPCA gives 10–21°C.

Prepare UK tap water

Add a tap water conditioner to every refill to remove chlorine or chloramine, and bring the water to the aquarium’s temperature first. Test your own supply and compare it on our water matcher; our water chemistry guide explains each reading. OATA says a heater is usually unnecessary unless the room is very cold.

Filter gently and keep a weekly routine

A filter is always essential, OATA says, but fancy goldfish prefer gentle flow: keep the output moderate or spread it with a spray bar. An air pump and airstone add oxygen without strong current. Our guide to aquarium filtration explains how to choose and size a filter.

Work through the weekly sequence

Practical Fishkeeping suggests a larger 50% weekly change where possible for telescope-type goldfish, so sources differ on volume; treat OATA’s 25% as the minimum. A new aquarium must be cycled first: the RSPCA advises fishless cycling for at least two weeks, and our article on the nitrogen cycle explains why.

Feed a measured daily meal

OATA recommends a quality flake, granule or pellet made for goldfish, which need more carbohydrate than many fish, fed once a day in an amount that is eaten within a few minutes. Daphnia, bloodworm, brine shrimp, soft aquatic plants, blanched lettuce and thawed, shelled peas make good extras. Overfeeding leaves food to rot and pollute the water.

Measure the meal

1. Offer a small amount of goldfish food such as Tropical Super Goldfish Mini Sticks.
2. Watch for a few minutes; stop when the fish slows down.
3. Replace part of the meal on some days with a thawed frozen food such as the Koi and Goldfish Special Frozen Blister.
4. Remove anything left over.

Some round-bodied goldfish gulp air at the surface and then struggle to stay level. If that happens, OATA suggests a different food or a slow-sinking one.

Introduce it to a mature aquarium

OATA asks you to check that ammonia and nitrite are at zero before any fish goes in, and to build up stock gradually to avoid new tank syndrome, when the filter bacteria cannot keep up with waste.

Follow a first-week plan

Our acclimatisation guide covers the floating bag method in more detail, and our delivery and Live Arrival Guarantee page explains dispatch and what to do if there is a problem.

Check a white fish for early warning signs

On a white fish, small changes show up clearly, which makes a daily look worthwhile. OATA lists the signs to act on: hanging at the surface or sitting on the bottom, colour darker or paler than normal, more hiding or aggression, breathing faster or slower than usual, white spots, fluffy growths, damaged fins or missing scales, clamped fins, flicking against objects, weight change and reduced appetite.

Pair each sign with an action

Mix it with fancy goldfish of a similar build

OATA says fancy goldfish can live alone or with other fancy goldfish, but not with common goldfish, which are faster, outcompete them for food and sometimes nip fins. The RSPCA gives the same advice for single- and twin-tailed types and says a goldfish does not need company. Practical Fishkeeping notes that fantails, ryukins and telescopes are equally easy to keep and can share a tank. FishBase suggests groups of five or more, so the sources differ on numbers; if you keep a group, add OATA’s 50 litres for each extra adult.

Screen each companion

Our tank mates tool checks a planned mix. Browse our fancy goldfish category or the wider goldfish and coldwater fish collection for suitable companions.

Decide between an aquarium and a pond

This is a point where the sources disagree. OATA advises that fancy goldfish are best kept in indoor aquariums only. The breeder quoted by the Bristol Aquarists’ Society raises young fantails indoors and then moves them to ponds, where they overwinter happily, and Practical Fishkeeping’s fantail breeder says goldfish are hardy enough to survive winter outdoors. For a single pet fantail, we recommend an indoor aquarium, where you can watch it daily and it never has to compete with fast pond fish.

If you do keep fantails outdoors

Keep them only with other slow fancy goldfish, never with comets, shubunkins or other fast pond fish, and check them as closely as you would indoors. Our page of cold water fish shows species bred for outdoor life. Never release a goldfish into a river, lake or the wild: OATA notes that it is illegal, harms the fish and can damage native habitats.

Breed fantails with a clear plan

Fantails are among the easier twin-tailed goldfish to spawn, but two published methods differ in detail.

Compare the two methods

Fancy goldfish breeders select hard: the breeder quoted by the Bristol Aquarists’ Society rears about 3,000 fantail fry a year and keeps about 20. Plan homes for every young fish before you start.

Answer red cap fantail goldfish questions

What is a red cap fantail goldfish?

A fantail goldfish, Carassius auratus, with a white body and fins and a red patch on top of the head. Like every fantail it has a short, rounded body and a divided, forked double tail held high.

Is a red cap fantail the same as a redcap oranda?

No. A redcap oranda grows a raised red cap of growth on top of its head and carries its tail below the horizontal. A red cap fantail has the same colour scheme on a fantail’s smooth head and high-held tail, and UK fantail breeders treat a hood on a fantail as a fault.

How big does a fantail goldfish get?

OATA gives fancy goldfish a maximum of about 20 cm. You receive a young fish of about 3–4 cm, so plan the aquarium for the adult.

What size tank does a red cap fantail need?

OATA advises at least 100 litres for one adult fancy goldfish plus 50 litres for each additional adult. The RSPCA gives at least 60 litres per goldfish. Both rule out bowls.

Will the red cap stay the same?

The size and shape of the red patch vary from fish to fish, and a young goldfish can still change as it grows. Good lighting keeps the red at its strongest. We cannot guarantee how the cap will look on the adult.

Does a fantail need a heater?

Not normally. OATA gives 4–25°C with 15–23°C as the best range and suggests a heater only in a very cold room; the RSPCA gives 10–21°C.

Which goldfish can live with a fantail?

Other twin-tailed fancy goldfish of similar size and speed: ryukins, orandas, broadtails, telescopes and moors. Keep it away from common goldfish, comets and shubunkins, which are faster and take the food.

Can fantail goldfish live in a pond?

Sources differ. OATA says fancy goldfish are best kept in indoor aquariums, while a Bristol Aquarists’ Society breeder keeps fantails outdoors in ponds. We recommend an indoor aquarium for a single pet fantail.

How long do fantail goldfish live?

OATA says fancy goldfish commonly live 6–8 years, with rare reports of more than 20. A UK fantail breeder quoted by the Bristol Aquarists’ Society gives about 10 years.

Consult the care references

• Bristol Aquarists’ Society: Fantail goldfish — UK fantail standard, accepted colours, hardiness, lifespan, pond keeping and a breeder’s method
• Bristol Aquarists’ Society: Redcap oranda — the redcap oranda standard, its raised cap and low tail, and why fantail-type fish are excluded
• Bristol Aquarists’ Society: Goldfish information — history of red and white goldfish, pigment cells and the effect of light and diet on colour
• Practical Fishkeeping: How to breed fantail goldfish — a good English fantail, faults including a hooded head, breeding method and winter hardiness
• OATA: How to look after fancy goldfish — adult size, lifespan, water values, tank volume, filtration, feeding, acclimatisation, warning signs, compatibility and breeding
• Practical Fishkeeping: How do I keep telescope eye goldfish? — fantails, ryukins and telescopes as compatible companions, footprint for three adults and water changes
• RSPCA: Choosing an aquarium for pet fish — space per goldfish, temperature range, wide tanks and fishless cycling
• RSPCA: Keeping pet fish together — goldfish kept alone and single- versus twin-tailed varieties
• FishBase: Carassius auratus — family, species water values and aquarium notes
• Tropical Fish Co delivery policy — current dispatch and Live Arrival Guarantee terms.