White Widow Tetra – White Skirt Tetra (Gymnocorymbus ternetzi)

Meet the White Widow Tetra (White Skirt Tetra)

The White Widow Tetra, also sold as the White Skirt Tetra, is a pale, selectively bred form of Gymnocorymbus ternetzi, the familiar black widow tetra. It has the same deep, rhomboid body and the large, skirt-like anal fin that gives the species its names, but the body is a pearly, silvery white with a soft cream sheen and the fins are clear to milky white. The eye stays dark, which marks it as a pale (leucistic) fish rather than an albino.

The wild species comes from small, slow-moving creeks and streams, usually with dense overhanging vegetation, in the Rio Paraguay and Guaporé basins of Brazil, Bolivia and Argentina, according to Seriously Fish. Every widow tetra in the trade is captive bred, and Seriously Fish rates it one of the better tetras for a general community aquarium and one of the best choices for a newcomer to fishkeeping. Kept in a proper shoal, a group of white widows makes a bright, moving contrast to green plants and darker fish.

Know the names and colour forms

All of these are one species, Gymnocorymbus ternetzi, so they share the same care and can be mixed in one shoal. FishBase now places the genus in the family Acestrorhamphidae, the American tetras; older books, Seriously Fish and OATA still list it under Characidae. Browse every form together on our Gymnocorymbus widow tetra page, or see the wider tetras range.

Know what one purchase supplies

One purchase is one live White Widow Tetra, supplied at a medium size. The price is per fish, so add the number you want to your basket: this is a shoaling fish and should never be kept alone. The photographs show the colour form, not the individual you will receive; they were prepared from a reference image of this form, and each fish varies slightly in size, sheen and fin shape.

A medium fish is a young, growing tetra rather than a full adult. It will fill out into the deep-bodied adult shape over the following months, so plan the aquarium for the adult size given below.

Build the shoal in one order

• Six fish: the practical minimum; FishBase and OATA both say groups of at least five.
• Twelve fish: Seriously Fish's figure for a shoal in which fin-nipping is usually kept within the group.
• Mixed forms: black, gold and white widows are one species and can make up one shoal together.

Before you order, read our delivery days and Live Arrival Guarantee so you are at home when the fish arrive and the aquarium is ready for the whole group.

Plan the aquarium for a shoal of twelve

Plan for an adult of about 6–7.5 cm. Seriously Fish gives a maximum of 60 mm standard length, while FishBase records 7.5 cm standard length; standard length is measured without the tail. The difference is small, but it is worth planning for the larger figure because the widow tetra is a deep-bodied fish with more bulk than a slim tetra of the same length.

Seriously Fish recommends an aquarium base of at least 75 × 30 cm, about 68 litres, for a group. FishBase gives a minimum aquarium length of 60 cm, and OATA recommends at least 80 litres for tetras of 5 cm or more. For a full shoal of twelve, work towards the larger figure.

Use a three-step space check

1. Measure the base: at least 75 cm long and 30 cm front to back; a long tank gives an active shoal more swimming room than a tall one of the same volume.
2. Count every shoal: add the full group of widows to the full groups of every other shoaling fish you plan to keep.
3. Plan on adult bodies: use 6–7.5 cm per widow tetra, not the size it arrives at.

Our stocking calculator checks a mixed community against your tank, and the first tropical tank guide explains how to set up and mature a new aquarium before any fish arrive.

Lay out open water with planted edges

Seriously Fish describes this tetra as fairly unfussy about décor: it is an active fish that wants plenty of open swimming space along with some quieter areas, and it shows its best colours with some dense planting and floating plants to dim the light. It will thrive in most layouts, which makes it easy to fit into an existing community.

Divide the tank by function

OATA recommends aquarium gravel or sand and, ideally, live plants for cover, with plastic plants and ornaments as an alternative. Keep the aquarium away from draughts, heat sources and direct sunlight. A white fish shows every speck of algae and debris on the glass behind it, so a tidy, well-planted tank shows this form at its best.

Set water values where the sources overlap

Captive-bred widow tetras are adaptable. Seriously Fish describes all the fish in the trade as unfussy about water chemistry, but the three main sources give different ranges, so the safest target is where they overlap.

Separate habitat values from waste readings

Many UK homes have hard tap water with a pH above 7. FishBase and OATA both accept up to pH 8.0, so a stable tank a little above the overlap is better than one pushed up and down with chemicals. Test your tap water and compare it with these ranges using our water matcher; the water chemistry guide explains what each reading means.

Filter and maintain for a lively shoal

For a 68-litre tank, Seriously Fish suggests a filter rated at 270–340 litres per hour, four to five times the tank volume, and a heater of roughly 50 W in a room at about 20°C. A shoal of active, deep-bodied tetras eats well and produces steady waste, so the filter must be mature before they arrive. Our guide to the aquarium nitrogen cycle explains how a new filter matures.

Follow a weekly maintenance sequence

1. Test ammonia, nitrite and nitrate, and note the results so slow changes show up.
2. Change at least 25% of the water, as OATA recommends every week.
3. Treat the new water with a dechlorinator that removes chlorine and chloramine, and match the temperature.
4. Siphon the gravel or sand where food collects.
5. Check filter flow; if the media needs cleaning, rinse it lightly in removed tank water, never under the tap.

Keep the heater and filter running all the time. A sudden drop in temperature or a stopped filter affects a whole shoal at once, so check both at every feed.

Feed small, varied meals once a day

Seriously Fish calls this "a most unfussy, omnivorous species". FishBase records that wild adults live in the middle and upper water layers and feed on worms, small crustaceans and insects. In the aquarium, a good flake or small granule makes the staple, with regular small live or frozen foods such as Daphnia and bloodworm.

Build one measured meal

• Staple: a quality flake or small granule that the fish can swallow whole.
• Variety: frozen or live Daphnia, bloodworm or brine shrimp a few times a week, in place of a dry meal rather than on top of it.
• Portion: only what the shoal finishes within a few minutes, once a day, as OATA advises.
• Spread: scatter food along the surface so every fish gets a share and the boldest cannot take it all.

Uneaten food that drifts to the floor breaks down into waste. If bottom fish such as Corydoras share the tank, give them their own sinking food rather than feeding the tetras more.

Introduce the shoal to a mature aquarium

Check that ammonia and nitrite read zero and that temperature, pH and hardness sit within the target ranges before the fish arrive. OATA's floating-bag method works well for tetras: lights off, float the bag for 10 minutes, then add small amounts of tank water over up to 20 minutes before netting the fish into the tank with as little bag water as possible. Our guide to acclimatising new fish shows each step.

Use a first-week checkpoint plan

Newly arrived fish often look paler or hide for a day or two. That settles as they find their place in the shoal; a fish that stays alone, stops feeding or breathes rapidly needs a water test straight away.

Keep a full shoal to curb fin-nipping

The widow tetra is generally peaceful and lively, but Seriously Fish notes it has a reputation as a bit of a fin nipper. The fix is numbers: in a shoal of at least 12, any squabbling is generally kept within the group. FishBase and OATA give five or more as the minimum, and fish kept singly or in too small a group often become stressed.

Screen companions with suits and avoid

Seriously Fish adds that the widow tetra's rounded shape means it is unlikely to be eaten by larger fish such as angelfish, but keep an eye on long-finned companions. Our tank mates checker compares temperature and size before you buy, and our tetra guide and beginner fish guide suggest community combinations.

Watch for health problems early

Pale fish make some problems easy to spot: white spots are harder to see on a white body, but reddening, frayed fins and cloudy patches stand out. Look over the whole shoal at each feed. OATA lists the signs to watch for in all fish: changes in swimming, colour, temperament, breathing, appearance, body condition and feeding.

Pair each observation with an action

Our guides to white spot treatment and fin rot cover the most common problems. If signs continue after you have corrected the water, contact us with your test results.

Breed white widow tetras

Seriously Fish describes the species as quite easily bred in a separate tank of about 18 × 12 × 12 inches, dimly lit, with fine-leaved plants such as java moss, spawning mops, or a mesh base that lets the adhesive eggs fall out of the adults' reach. Group spawning works with about half a dozen of each sex. For pair spawning, condition males and females separately at about 24–25.5°C on live and frozen foods, then move the fullest female and best-coloured male to a spawning tank at about 28–30°C with slightly acidic water; they usually spawn the following morning.

Remove the adults as soon as eggs appear, because they eat them. The eggs hatch in 18–36 hours and the fry swim freely a few days later; feed infusoria first, then microworm or brine shrimp nauplii, and keep the tank dim because eggs and fry are light-sensitive. Males are noticeably slimmer, a little smaller and have more pointed dorsal and anal fins than females.

Answer White Widow Tetra buying questions

Is a white widow tetra the same as a white skirt tetra?

Yes. Both are trade names for the same pale, selectively bred form of Gymnocorymbus ternetzi, the species better known as the black widow or black skirt tetra. Seriously Fish notes that the leucistic form is often sold as the white skirt tetra.

Is the white widow tetra dyed?

No. It is a colour form bred for its pale body, not a dyed fish. Seriously Fish warns against artificially dyed widow tetras, which are injected with colour, a process that is very stressful and often shortens their lives considerably.

How many white widow tetras should I keep?

At least six, and ideally twelve. FishBase and OATA give groups of five or more as the minimum, and Seriously Fish says a shoal of at least 12 usually stops the fin-nipping the species is known for.

How big do white widow tetras grow?

About 6–7.5 cm in body length. Seriously Fish gives 60 mm standard length and FishBase 7.5 cm standard length; standard length leaves out the tail.

What size tank do they need?

Seriously Fish recommends a base of at least 75 × 30 cm, about 68 litres, for a group, and OATA recommends at least 80 litres for tetras of 5 cm or more. A full shoal of twelve is happiest at the larger end.

What water suits a white widow tetra?

Aim for 22–26°C, pH 6.5–7.0 and 5–12 dGH, where Seriously Fish, FishBase and OATA overlap. Captive-bred fish are adaptable, so a stable tank slightly outside this is better than one that keeps changing.

Which fish can live with white widow tetras?

Livebearers, danios, rasboras, other tetras, Corydoras, smaller plecos and robust dwarf cichlids such as kribensis, as Seriously Fish suggests. Be careful with slow, long-finned fish unless the widows are in a full shoal.

How is it different from your Gold Widow Tetra?

Both are pale forms of the same species. This listing is the white-bodied fish with dark eyes shown in the photographs; trade names for the pale forms overlap, so if you want a warmer gold tone, look at the Gold Widow Tetra instead.

Consult the care references

• Seriously Fish: Gymnocorymbus ternetzi, Black Widow Tetra — distribution, habitat, size, aquarium base, décor, water values, filter and heater sizing, diet, fin-nipping and shoal size, companions, sexing, breeding and the white skirt and dyed forms.
• FishBase: Gymnocorymbus ternetzi, Black tetra — current family (Acestrorhamphidae), distribution, environmental ranges, maximum length, wild diet, group size and minimum aquarium length.
• OATA: How to look after tetras and pencilfish — UK group guidance on water quality limits, aquarium size, maintenance, acclimatisation, feeding and warning signs.
• Tropical Fish Co delivery policy — current dispatch days and Live Arrival Guarantee terms.