The black skirt tetra is a deep-bodied characin from the Paraguay and Guapore river basins, recognised by its silvery-grey body, twin black bars and dark flowing anal fin.
Larger and sturdier than most tetras, it is a long-standing community favourite.
It is hardy and adaptable, tolerating a range of conditions, which makes it beginner-friendly.
Be wary of dyed or injected colour variants, which raise welfare concerns and often show reduced vitality.
Housing
Keep a shoal of at least six in 75 litres (20 gallons) or more, filtered and heated to 22-27C.
Their adult size and active swimming call for more horizontal space than tiny tetras, with planted edges and driftwood framing open swimming room.
They accept a range of soft to moderately hard water but value stability most.
A well-cycled tank with steady parameters and gentle to moderate flow suits their robust temperament.
Diet
Black skirts are unfussy omnivores.
A quality flake or pellet forms a reliable staple, rotated with frozen or live bloodworm, daphnia and brine shrimp, plus occasional plant-based or algae food for balance.
Feed small amounts once or twice daily, only what is consumed in a minute or two.
They eat enthusiastically and can outcompete shy tankmates, so make sure slower feeders also reach the food.
Health
These are among the more disease-resistant tetras, with most problems traceable to chilling, poor water quality or stress.
Ich and fin rot are the usual concerns and respond well to corrected conditions and early treatment.
Long-finned varieties are more prone to fin nipping and damage.
Quarantine new stock, maintain weekly partial water changes, and avoid dyed or injected colour-variant fish, which carry higher disease and mortality risk.
Temperament
Generally peaceful but semi-active, black skirts can become nippy, especially toward long, flowing fins, when kept in groups that are too small.
A shoal of six or more diffuses this behaviour and keeps them calmer.
They suit lively community tanks with similarly sized, robust species and open swimmers.
Avoid pairing them with slow, long-finned fish such as bettas or fancy guppies, and keep them in numbers to reduce fin-nipping.
A good fit for
Beginners wanting a hardy, forgiving shoaler
Active mid-sized community aquariums
Keepers in areas with variable tap water
Those who like a bold, contrasting fish
Common mistakes to avoid
Fin-nipping when kept in too-small groups
Pairing with slow, long-finned tankmates
Buying dyed or injected colour variants
Undersized tanks limiting their active swimming
Is your enclosure big enough?
Minimum volume75 litres (20 US gallons)
CompanyCannot be kept alone. The minimum is 6, and the space above is for that group.
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, or crowding the filter outflowIncrease surface agitation immediately, then test the water. Either the oxygen has crashed or the gills are being chemically burned. Both are hours-scale problems.
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 point at the water or the equipment, not at a pathogen.
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.
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.
Intermediate
Intermediate
Beginner
Intermediate
Beginner
Beginner