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Veiltail Goldfish
Freshwater Fish · Goldfish

Veiltail Goldfish

Carassius auratus

Rare long-finned fancy with a square-cut veilAdvanced

Lifespan
10-15 years
Size
6-10 in including the tail
Social needs
Social - keep 5+ together
Time
High (daily fin checks, frequent water changes)
Cost
High
Diet
Omnivore

Overview

What is this animal?

  • The veiltail is a fancy goldfish developed in Philadelphia from Japanese fringetail goldfish imported in 1893, and later developed further in Britain.
  • It has a short, round, deep body with a smooth back and no hump, a tall dorsal fin carried high and erect, and a long, broad double tail that hangs in folds, its trailing edge cut square with no fork.
  • True veiltails are rare, and many fish sold under the name are long-finned fancies with a forked tail.
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  • Much of a veiltail's length is fin, and with the tail a large adult reaches about 8-10 in.
  • Those fins are the point of the breed and its main welfare cost: they tear easily, become infected, and in older fish can grow so heavy that the fish struggles to carry them.

Temperament

  • Veiltails are peaceful, gentle and slow, and they are social fish that should be kept in a group of at least five.
  • Keep them only with other slow, round-bodied fancies of a similar size, and best of all with other veiltails.
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  • Never mix them with comets, commons or other active goldfish, which outcompete them for food, and keep them away from tropical fish and any fin-nipper.
  • A calm, single-variety tank gives the fins the best chance of staying whole.

A good fit for

  • Experienced fancy goldfish keepers
  • Calm, indoor, single-variety setups
  • Keepers with room for a custom tank at least 8 ft long
  • People committed to daily fin checks for 10+ years

Common mistakes to avoid

  • Torn fins from sharp decor, rough plants or fin-nippers
  • Fin rot when water quality slips
  • Long-finned fancies with forked tails sold as veiltails
  • Mixing with fast goldfish that take all the food

Enclosure

Minimum 250 gallons, for a group of 5

Cannot be kept alone. The minimum is 5, and the space above is for that group.

  • Veiltails are coldwater fish kept indoors all year, unheated in a room that stays at about 64-73°F.
  • One UK breeder advises against keeping them outdoors, because they suffer in hard frosts and, in green water during hot spells, gas bubbles can tear their tails.
  • Keep a group of at least five in a tank at least 8.5 ft long with at least 30 in of water depth, about 248 US gallons or more.
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  • The length is ten times, and the depth three times, the full adult length of the largest fish, tail included, so veiltails that stay at 8 in need 6.5 ft and 24 in; a tank of the full size is usually a custom build.
  • Everything in the tank must be smooth: fine sand, rounded stones and soft live plants, with no sharp rock, rough wood or stiff plastic plants for the fins to catch on.
  • Keep the flow gentle and the filtration strong, and do large, frequent water changes, because a torn fin is an entry point for infection and dirty water is where the infection comes from.

Check your enclosure

Supplies

Setup

  • Tank and stand, at least 8.5 ft long with 30 in of water
  • Filters
  • Thermometer
  • Substrate, plants and decor
  • Liquid test kit
  • Dechlorinator and starter supplies

Ongoing

  • Sinking goldfish pellets or gel food
  • Frozen peas (to deshell and blanch)
  • Courgette and spinach for blanching
  • Veg clip
  • Frozen bloodworm or daphnia
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  • Small cup for pre-soaking pellets
  • Fine net for removing leftovers

Safe substrate: Fine, smooth sand · Smooth, rounded fine gravel (not for loaches or sand-sifting cichlids; sand is better for corydoras) · Bare bottom (quarantine and grow-out only)

Work out the cost

Care routine

Daily

  • Check temperature and equipment
  • Feed a sinking, pre-soaked food
  • Head-count and look everyone over

Every few days

  • Top up evaporationevery 3 days

Weekly

  • Large water change
  • Test the water
  • Wipe the front glass only
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Every few weeks

  • Rinse the filter mediaevery 2 weeks
  • Trim and thin the plantsevery 2 weeks

Monthly

  • Check supplies and reagent dates
  • Replace or recharge chemical media, if you use any (skip it in a blackwater tank)

Health review: Quarterly water and buoyancy review, every 3 months

Tools

Is your enclosure big enough?Check your measurements against the recommended sizeWhat will it cost?Setup, monthly and over its whole life, itemisedIs this ammonia reading dangerous?Works out the toxic part from your pH and temperature

Care in depth

Diet

Omnivore
  • Veiltails are omnivores with round bodies that are prone to buoyancy trouble, so feed a quality sinking goldfish pellet or gel food as the staple, with plenty of blanched vegetables and other plant matter and occasional frozen bloodworm or daphnia.
  • Pre-soak dry food, which reduces gulped air and bloating.
  • They are slow and cannot compete with active goldfish, so make sure each fish gets its share, feeding small meals once or twice a day and removing what is left after a couple of minutes.
  • Good feeding matters for the fins too: poorly fed veiltails develop ragged, congested fins.

Health

Signs of good health, and the common problems
  • The long fins are where most veiltail problems start.
  • They tear on sharp decor, are nipped by other fish, and turn cloudy, ragged or streaked with red when water quality slips and fin rot sets in.
  • Look over every fish's fins daily for splits, fraying, white edges or red streaks, and put the water right first.
  • It is not unusual for veiltails to lose their balance as they mature, and older fish with heavy tails often sit on the bottom, stand on their tails or rest among the plants.
  • Watch for floating, sinking or tilting after meals, clamped fins and flicking, and keep the tank fully cycled with frequent water changes, because veiltails are very sensitive to ammonia and nitrite.

Is this urgent?

6 warning signs and how fast to act, 3 of them right away

In a fish tank the patient is usually the water. Test before you treat: dosing a healthy tank for a disease it does not have makes things worse.

Go now

Any detectable ammonia or nitrite in a stocked tankLarge water change now with dechlorinated, temperature-matched water. Stop feeding. Test again in 12 hours. Both are directly toxic. How toxic the ammonia reading is depends on pH and temperature, so the same number can be harmless or lethal.
Now
Fish gasping at the surface with fast gill movement, or crowding the filter outflowIncrease surface movement now (gently in a betta or gourami tank, without creating a strong current), then test the water. Either the oxygen has crashed or the gills are being chemically burned. Both are hours-scale problems. Bettas, gouramis and corydoras rise to gulp air as part of normal breathing; the warning is constant gulping, fast gill movement, or the whole group hanging at the top.
Now
Sudden deaths, more than one fish in a dayTest ammonia, nitrite, nitrate and temperature before doing anything else. Do not add medication yet. Multiple simultaneous deaths usually point at the water or the equipment rather than a pathogen, so rule those out first.
Now

Today

Flashing: repeatedly scraping against decor or substrateTest the water, then look closely for parasites. Irritation is either chemical or parasitic; the test tells you which before you medicate.
Today
White salt-grain spots over the body and finsBegin the appropriate treatment today and check the temperature. The parasite's life cycle is temperature-driven, and it multiplies with every cycle you wait.
Today

Soon

Clamped fins, hiding, or refusing food for more than two daysTest the water and review recent changes. Usually the earliest visible sign of a parameter drifting.
A few days

Never add a new fish to a tank that is not fully cycled, and never treat blind. A test kit is cheaper than the fish.

This is general guidance for a healthy adult, not a diagnosis. An exotics vet who knows your animal always overrides it, and the time to find one is before you need one.

Bedding and substrate

3 safe, 4 with a caveat, 2 to avoid

Substrate in an aquarium is a filter as much as a floor. Most of the biology lives in and on it.

Safe

Fine, smooth sandCorrect for corydoras, kuhli loaches, eartheaters such as rams and acaras, and anything else that sifts or burrows. Barbels wear away on sharp gravel.
safe
Smooth, rounded fine gravel (not for loaches or sand-sifting cichlids; sand is better for corydoras)Rinse thoroughly before use. Grain size should be too large to swallow and too small to trap food. Kuhli loaches need sand to burrow into and rams and acaras sift mouthfuls of it; bronze and panda corydoras manage on smooth fine gravel, but sterbai corydoras need sand.
safe
Bare bottom (quarantine and grow-out only)Legitimate for quarantine and grow-out tanks. Easy to clean, but it holds far less biological filtration, and it is no long-term home for burrowing loaches or sand-sifters.
safe

With a caveat

Crushed coral or aragoniteDeliberately raises hardness and pH. Correct for rift-lake cichlids, wrong for soft-water species.
with a caveat
Aquasoil for planted tanksExcellent for plants, but most active soils soften the water and pull pH and KH down for months, and many leach ammonia for the first weeks. Right for soft-water species; wrong for hard-water animals (livebearers, rainbowfish, goldfish, and snails, whose shells erode in soft, acidic water) unless you test GH and KH and remineralise. Cycle around it; do not stock into it.
with a caveat
Very deep sand bedsAnaerobic pockets form below about 2 inches in still sand. Either keep it shallow or keep it stirred.
with a caveat
Painted or coated gravelUsually fine, but coatings chip. Test a handful in a jar for a week first.
with a caveat

Never

Sharp or angular gravel with bottom-dwellersWears down barbels and leads to infection in corydoras and loaches.
never
Anything containing metal, limestone of unknown origin, or shells in a soft-water tankSlowly alters chemistry in ways that are hard to diagnose later.
never

This is our general list for freshwater fish. We have not built one specific to Goldfish yet.

Top resources for more info

Independent creators and organisations we would send a friend to. We have no affiliation with any of them, and nothing here is sponsored. Links checked 2026-10-22.

YouTubers

Luke's GoldiesGoldfish keeping indoors and in ponds, from a breederGirl Talks FishCare how-tos by fish type, tank setup and beginner mistakes (the host works for Aquarium Co-Op, a retailer)Aquarium Co-OpSpecies care guides, filtration and fish health (run by a retailer)

Sites

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Is your enclosure big enough?

These are the smallest sizes that give good conditions, not legal minimums. More room is always better.

Minimum 250 gallons, for a group of 5

Every figure, and where it comes from

250 gallons is for a group of five veiltails, in a tank at least 8.5 ft long with at least 30 in of water depth. Austrian law requires a goldfish tank at least ten times as long, and three times as deep, as the full adult length of its largest fish, and at least five goldfish kept together. Much of a veiltail's length is tail: a body of up to about 5 in and a tail at least three-quarters as long, and in the best fish as long as the body, come to about 10 inches in all. The welfare-led sources ask for less, about 47 in and two or more fish, and this site sets its figure at that legal minimum because good conditions are never less than a law requires. Veiltails that stay at 8 in need 6.5 ft and 24 in, and a fish whose tail grows longer needs more.

Minimum volume250 gallons
Swimming length8 ft minimum. A tall tank of the right volume is still the wrong shape.
CompanyCannot be kept alone. The minimum is 5, and the space above is for that group.
The recognised standards do not agree on this one
Austria, 2. Tierhaltungsverordnung, Anlage 5: A tank at least 10 times as long and 3 times as deep as the full adult total length of the largest fish, at least 39 x 16 x 20 in (53 gallons), and at least five goldfish kept together. A legal minimum. The welfare-led sources ask for less, so this is the length, depth and group this site uses: good conditions are never less than a law requires. Checked 2026-10-23.
Nationwide Goldfish Standards of the United Kingdom (2016), veiltail: Tail divided and held below the horizontal, with no apparent fork or pointed lobes, ideally at least 75 percent of the body's length; dorsal fin carried high and erect. A breed standard, not a tank size: the tail length behind the adult length used here. Checked 2026-10-23.
about-goldfish.com (goldfish care site): A body length of up to 5 in; a high-quality veiltail's fully divided tail is as long as the body or longer. The body and tail behind the 10 in used here. Checked 2026-10-23.
Practical Fishkeeping (UK), fancy goldfish guide: A tank at least six times as long and twice as wide as a typical adult. Less length than the figure used here: 59 in for a 10-inch fish. Checked 2026-10-23.
Swiss Animal Protection STS: A goldfish aquarium at least 47 in long and 20 in wide; goldfish are shoaling fish and must not be kept alone. Less length than the figure used here. Checked 2026-10-23.
RSPCA Australia: Length at least 4 times, width 2 times and height 3 times the adult body length, and never under 13 gallons. Its width, 20 in for a 10-inch fish, is the width behind the volume used here, and its height, 30 in, matches the depth; its length is less. Checked 2026-10-23.

What it really costs

Setup, monthly, first year and across a whole life, itemised and with the electricity worked out from the actual wattage. Published figures for the same animal disagree by a factor of four, so the calculator shows ranges rather than picking one.

My kit says 0.25 ppm. Is that dangerous?

A liquid kit measures total ammonia, but only the un-ionised fraction is really toxic, and that fraction is governed by pH and temperature. Each whole pH unit multiplies it roughly tenfold. So the same reading can be nearly harmless in one tank and lethal in another; this works out which one you are in.