Species profile
Black Skirt Tetra
Gymnocorymbus ternetzi
Semi aggressive
Easy care
80 L minimum aquarium
5–7.5 cm adult size
Midwater
Minimum group: 8
About this species
General notes for hobby use.
Hardy schooling tetra; under-sized groups can become persistent fin nippers.
Water parameters
Suggested general range for long-term care.
Temperature
18–26 °C
pH
6–7.5
GH
2–18 dGH
KH
Not yet documented
Flow preference
Low–moderate
Data confidence
Verified
Behaviour
General behaviour traits used by TanksConnected compatibility checks.
Minimum group size
Minimum group: 8
Tank zone
Midwater
Territory level
Low
Predation risk
Tiny fry
Bioload factor
0.8
Keep eight or more so social sparring is directed within the shoal. Avoid slow long-finned tankmates where nipping becomes persistent.
Compatibility flags
Quick cautions for common tank-planning issues.
Fin nipper
Yes / caution
Plant safe
Yes
Shrimp safe
No / caution
Snail safe
Yes
Cave breeder
No
Digs substrate
No
Jump risk
Low
Natural history & care
Research-backed context for long-term aquarium care.
Lifespan
Not yet documented
Diet type
Omnivore
Minimum aquarium volume
80 L
Minimum footprint
80 × 30 cm
Accepted scientific name
Gymnocorymbus ternetzi
Alternative names
Black Skirt Tetra, Black Widow Tetra, Gymnocorymbus ternetzi
Native range
Paraguay and Guaporé river systems of South America.
Natural habitat
Vegetated freshwater margins and slower reaches. Combine planting/cover with an open mid-water shoaling area.
Diet & feeding
Generalist feeding on worms, small crustaceans and insects; offer quality dry foods plus varied small frozen/live foods.
Breeding & sexing
Research-backed guidance for identifying sexes and reproductive behaviour.
Sexing
Females are usually larger and deeper-bodied; mature males tend to be slimmer with more pointed fin shape.
Breeding
Egg-scattering characin with no parental care; use a separate breeding setup if fry survival is wanted.