| Temperature | 22–28 °C (72–82 °F) |
|---|---|
| pH | 6.0–7.5 |
| Min tank | 15 gal (57 L) |
| Adult size | 7 cm |
| Lifespan | 5–7 years |
Most people buy a Black skirt tetra on looks alone, then wonder why it sulks. The fish is fine; the setup around it usually is not. The Gymnocorymbus ternetzi Black skirt tetra is a long-time favourite for a reason, but it has specific needs that generic "community fish" advice misses.
At a glance
| Minimum tank | 15 gallons (57 L) |
|---|---|
| Temperature | 22 to 28 °C |
| pH range | 6.0 to 7.5 |
| Adult size | 6 to 7 cm |
| Lifespan | 5 to 7 years |
| Group size | a group of 6+ |
Where it comes from
In the wild the Black skirt tetra lives in slow, vegetated waters where cover is everywhere and currents stay gentle. Recreating that means planting densely, keeping the filter flow soft, and avoiding bright, open tanks that leave the fish exposed. Stable water matters more than perfect parameters.
Tank setup
Start with at least 15 gallons and a mature, cycled filter — see a solid why is my fish not eating? before you buy. A sand or fine gravel substrate, a few driftwood branches and a carpet or mid-ground plant mass give the fish somewhere to retreat. Keep nitrates under 20 ppm with a weekly 27% water change.
Feeding
Feed a varied diet: a quality flake or micro-pellet as the base, topped up with frozen or live foods two or three times a week. Offer only what the fish clears in about 2 minutes, once or twice daily. Overfeeding is the single most common cause of water-quality swings.
A mistake everyone makes
Adding a Black skirt tetra to a brand-new tank is the classic error. An uncycled tank spikes ammonia to 1.6 ppm within days and the fish pays for it. Cycle first, stock lightly, and let the group size build up gradually.
Good tank mates
Peaceful, similar-sized neighbours work best. Avoid fin-nippers and anything large enough to swallow the Black skirt tetra. A planted community with a solid canister vs hang-on-back filter: which should you run? in the mix tends to settle quickly.
In a planted tank
A densely planted 15-gallon setup suits the Black skirt tetra well: the plants soften the light and give cover, while the fish's foraging stirs the substrate. Keep nitrates under 20 ppm and trim so the Black skirt tetra still has open swimming lanes.
