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.
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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.
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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.
