Black neon tetra

Geographic Origin and Biotope: Rio Paraguay Basin (Mato Grosso). Swims in still or very slow waters, dark (Igapó) or clear but still densely shielded by marginal plants.

Taxonomy and Morphology: Black Neon Tetra (Hyphessobrycon herbertaxelrodi). Not a true Neon (genus Paracheirodon), but a taller and more compact cousin of the Hyphessobrycon clade. Characteristic large eye.

Social Behavior: Strictly schooling (10+). If kept in small numbers it becomes shy or stressed. In large schools it swims in an hypnotic and compact manner in the medium-high range.

Coloration and Sexual Dimorphism: Olive-gray background with two longitudinal bands side by side: a superior iridescent greenish-white/golden one and a thick velvety black inferior one. Bright red upper iris. Females are noticeably more swollen.

Aquarium Setup: Seeks dark contrasts. Black gravel or dark bottom and dim lighting (or abundant floating plants) are a must to make the iridescent line light up; on white backgrounds it fades enormously.

Diet and Feeding: Omnivore (Micro-predator). Feeds at the surface or in mid-water, ignoring remains on the bottom. Crumbled flakes, live brine shrimp and frozen bloodworms are perfect.

Water Quality: Very resistant for a "Neon", tolerates treated tap water well, but prefers slightly acidic water (pH 6.5) for full health and coloration.

Compatibility and Tankmates: The perfect choice for a peaceful Amazonian tank. Ideal with Discus (does not fear warm temperatures unlike classic Neons), Angelfish (if large enough not to be eaten), and Loricariids.

Aquarium Reproduction: Moderately difficult Egg-scatterer. Spawns in groups on dense mosses; eggs hatch in 24 hours. The use of a net on the bottom of the breeding tank saves the eggs from hungry parents.

Risks and Diseases: Less prone to Neon Tetra Disease (Pleistophora) than the classic Neon, but sensitive to Ichthyophthirius (White spots) in case of cold thermal shocks.