Black Neon Tetra (Hyphessobrycon herbertaxelrodi)

Hyphessobrycon herbertaxelrodi, the Black Neon Tetra, is a classic aquarium species that has been a staple of the planted tank and community aquarium hobby for decades. Despite sharing a common name with the Neon Tetra, it belongs to a different genus and presents a distinctly different aesthetic — two horizontal stripes run along the body: an iridescent greenish-white upper stripe and a bold, deep black lower stripe, creating an elegant two-tone pattern that complements green planted aquariums beautifully.

Native to the upper Paraguay River basin in Brazil (Mato Grosso), the Black Neon Tetra inhabits slow-moving blackwater streams and floodplain pools with dense vegetation and tannin-stained water. In its natural habitat, water is very soft, warm, and acidic — conditions that favour the most vivid iridescent stripe colour in the aquarium.

Black Neon Tetras grow to approximately 4 cm and are exceptionally peaceful, posing no threat to any tank mate. They are a schooling species that should be kept in groups of eight or more — in a large group in a planted aquarium, their coordinated swimming and glinting stripes create a mesmerising display.

This species is more tolerant of a range of water conditions than the Neon Tetra, making it suitable for moderately hard water as well as the ideal soft, acidic conditions. It is a reliable, long-lived (5+ years), and thoroughly rewarding fish for any planted community setup.

Tank Setup: A 60-litre minimum for a school of eight or more. Dense planting with fine-leaved species (Java fern, Hornwort, Rotala, Hygrophila), open mid-water swimming corridors, and dark substrate to enhance the iridescent stripe colouration. Gentle water flow — a sponge filter or diffused output. Indian almond leaves or peat filtration for soft, slightly tinted water brings out the best colour.

Water Parameters: Temperature 22–28°C; pH 5.5–7.5; GH 2–12 °dH; KH 1–8 °dH. Adaptable to a moderate range of conditions. Best colour achieved in soft, slightly acidic water.

Feeding: Omnivore. Accepts quality micro flake, small pellets, frozen baby brine shrimp, Daphnia, and micro worms. Feed twice daily in small amounts. Small mouths — ensure appropriate food particle size.

Tank Mates: Ideal with any peaceful species of similar size: Neon Tetras, Cardinal Tetras, Ember Tetras, Harlequin Rasboras, Pygmy Corydoras, Otocinclus, small Gouramis, and Apistogramma. Avoid large or aggressive fish and fin-nippers.

Behaviour: Peaceful schooling fish. Groups of 10+ school most tightly and display most attractively. Active during daytime, resting in lower vegetation at night. No aggression toward any species.

Health: Hardy and long-lived. Susceptible to ich and velvet under stress or sudden temperature drops. Avoid large water changes with very different temperature or chemistry. Regular 20–25% weekly changes maintain excellent health.