Black Widow Tetra Gymnocorymbus Ternetzi 2cm

Overview

The Black Widow Tetra, also called the Black Skirt Tetra, is a deep-bodied fish with two vertical bars and a sooty black rear half that fades to grey with age. Its flowing anal fin gives it a distinctive skirted look. Native to the Paraguay basin of South America, it suits active community tanks and beginners.

• Adult Size: Around 6 cm (2.4 in)
• Lifespan: 5–7 years

Origin

• Native to: Paraguay and Guaporé basins: Brazil, Bolivia, Argentina
• Habitat: Slow creeks and streams under overhanging vegetation

Feeding

• Diet: Omnivorous
• Preferred Foods: Flake, granules, daphnia, bloodworm, brine shrimp, spirulina flake
• Feeding Habits: Feed once or twice daily; varied diet keeps body deep

Tank Mates

• Best with: Danios, rasboras, robust tetras, corydoras, livebearers
• Avoid: Long-finned fish such as guppies, bettas and angelfish; timid species

Aggression & Behaviour

• Temperament: Generally peaceful, can be boisterous
• Territoriality: Low; fin nipping if kept in small numbers

Experience Level

• Difficulty: Beginner
• Challenges: Needs a large shoal to curb nipping

Water Parameters

• Water Type: Freshwater, soft to moderately hard
• Temperature: 20–26°C (68–79°F)
• pH: 6.0–7.5
• Hardness: 5–20 dGH
• Flow: Slow to moderate
• Tank Size: Minimum 80 litres for a shoal of eight or more

Final Notes

Keep at least eight, ideally more, as small groups are prone to nipping slower tank mates. The black colouring is strongest in young fish and fades to silver grey with age, which is normal. Black Widows are hardy egg scatterers that spawn readily over fine plants, with males slimmer and females fuller bodied. Give them open swimming space with planted edges. A robust, long-lived tetra.