Gymnocorymbus ternetzi
Tall-bodied tetra with two prominent vertical bars and a black 'skirt' anal fin. Fades to silver-grey in adulthood, buy the bold black juveniles knowing they'll mellow. Long-finned 'longfin' variant is widely sold but more prone to fin-rot in warm tanks. Avoid keeping with bettas or guppies.
Black Skirt Tetra (Gymnocorymbus ternetzi) reaches 5–6 cm as an adult and needs a minimum tank of 80 L. Native to Paraguay, southern Brazil, northern Argentina, it lives in the mid water column with a peaceful (occasional fin-nipper) temperament. Aim for 20–26 °C, pH 6.0–7.5, and 4–15 dGH hardness. Lifespan is 3–5 years with good care. Keep black skirt tetra in groups of 6+, yes schoolers need numbers to display natural behaviour. Diet: omnivore, Flake, micro pellets, frozen daphnia, brine shrimp. Plant-safe: Yes. Shrimp-safe: Adults only.
Care at a glance
Tall-bodied tetra with two prominent vertical bars and a black 'skirt' anal fin. Fades to silver-grey in adulthood, buy the bold black juveniles knowing they'll mellow. Long-finned 'longfin' variant is widely sold but more prone to fin-rot in warm tanks. Avoid keeping with bettas or guppies.
By Mike ElmiraUpdated 1 min read
Part of our complete guide to aquarium fish for the planted tank.
The parameters that decide whether black skirt tetra fits in your tank.
Mid
Yes
Group of 6+
Characidae
Omnivore
Flake, micro pellets, frozen daphnia, brine shrimp.
3–5 yrs
Medium
Slow tributaries of the Paraguay and Guaporé rivers
Paraguay, southern Brazil, northern Argentina
Tank-mate safety and the species this one is documented to thrive (or fail) alongside.
Direct answers to the questions search engines and AI assistants surface most often about this species.
Black Skirt Tetra (Gymnocorymbus ternetzi) needs a minimum tank of 80 L. They live in the mid water column and should be kept in groups of 6+, so a longer footprint matters more than depth.
Target 20–26 °C, pH 6.0–7.5, and 4–15 dGH hardness. Acclimate slowly when moving them between water sources.
Shrimp safety: Adults only. Plant safety: Yes.
Black Skirt Tetra are omnivore. Flake, micro pellets, frozen daphnia, brine shrimp.
On Fin & Stem's 1–5 difficulty scale this species rates 1/5. Almost unkillable, a solid first-tank choice. Breeding difficulty: medium.
Typical lifespan in a well-maintained tank is 3–5 years.
A planted tank is a system. Pair this fish with one entry from each other pillar to plan the whole scape.
