Black Widow Tetra (Gymnocorymbus ternetzi)
 
The Black Widow Tetra, also known as the Black Skirt Tetra, is a hardy and peaceful schooling fish popular in community aquariums. Recognised by its silver body, vertical black bars, and flowing dark fins, it adds movement and contrast to planted or community setups.
 
Care Sheet
Scientific Name: Gymnocorymbus ternetzi
Common Name: Black Widow Tetra, Black Skirt Tetra
Origin: South America – Paraguay and Guaporé River basins
Max Size: 5–6 cm
Lifespan: 3–5 years
Temperament: Peaceful, shoaling
 
Aquarium Requirements
Tank Size: Minimum 60 litres
Temperature: 22–28°C
pH: 6.0–7.5
Hardness: 5–15 dGH
Aquascape: Well-planted tank with open swimming areas
 
Diet
Omnivorous; accepts flakes, pellets, live and frozen foods (brine shrimp, daphnia, bloodworms).
A varied diet helps enhance colouration and vitality.
 
Compatibility
Best kept in groups of at least 6 to reduce fin-nipping behaviour.
Suitable tankmates include tetras, rasboras, Corydoras, dwarf cichlids, and gouramis.
Avoid long-finned slow fish (e.g., angelfish, bettas), as nipping may occur if not kept in a shoal.
 
Breeding
Egg scatterer with no parental care.
Condition with high-quality live and frozen foods.
Provide fine-leaved plants or a breeding mop for egg deposition.
Remove adults after spawning to prevent egg predation.
 
Summary: A hardy, peaceful schooling tetra with striking black markings and flowing fins. Perfect for community tanks when kept in groups, offering both movement and contrast.