Black Widow Tetra

Gymnocorymbus ternetzi, commonly known as the black tetra or black skirt tetra, is a popular freshwater fish recognized for its striking appearance. It features a deep, tetragonal silver body with two prominent vertical black bars behind the gills and a flowing, skirt-like black anal fin.

Natural Habitat and Origin

• Native Range: Found in the Paraguay and Guaporé River basins in South America, including regions of Brazil, Argentina, and Bolivia.
• Environment: Prefers subtropical, slow-moving streams and tributaries with dense vegetation and soft substrates.

Aquarium Care and Requirements

• Size: Grows up to 5 to 7.5 cm (2 to 3 inches) in length.
• Lifespan: Typically 3 to 5 years.
• Water Temperature: Thrives in temperatures between 20°C to 26°C (68°F to 79°F).
• Water pH: Best suited for a pH range of 6.0 to 7.5.
• Minimum Tank Size: Requires a tank of 15 to 20 gallons, ideally kept in a school of 5–6 individuals or more.
• Diet: Omnivorous/micropredator; readily accepts flakes, pellets, and live or frozen foods such as brine shrimp and bloodworms.

Behavior and Compatibility

• Temperament: Generally active and peaceful, though minor fin-nipping behavior may occur if kept in too-small groups.
• Schooling: Highly gregarious; keeping them in larger groups (8+) helps reduce internal squabbling.
• Tank Mates: Best suited for peaceful community fish such as danios, rasboras, livebearers, and bottom-dwellers like corydoras. Avoid housing them with long-finned or slow-moving species that may be vulnerable to nipping.

This stunning species is a fantastic addition to any aquarium, bringing life and elegance to your aquatic environment.