Vorderwinkler's Tetra

Geographic Origin and Biotope: Endemic to the middle and upper Rio Negro basin in Brazil. Typical species of pristine black waters (Blackwater), it swims among dense flooded forests rich in tannins and substrates formed by dried leaves and branches.

Taxonomy and Morphology: Vorderwinkler's Tetra (Hemigrammus vorderwinkleri). Small characin with a slender, ovoid shape. Relatively large eye to aid vision in dark waters, and a forked caudal fin.

Social Behavior: Gregarious, shy, and peaceful nature. To overcome its intrinsic shyness, it must be kept in schools of at least 8-10 individuals. Males form small temporary hierarchies without ever injuring themselves.

Coloration and Sexual Dimorphism: Semi-transparent body tending towards olive-yellow, with a delicate iridescent golden lateral line. The upper half of the eye is lit with a soft orange-red. Mature females have a much rounder abdomen.

Aquarium Setup: An amber biotope aquarium is ideal. Peat filtration, little or no direct light (shielded by Pistia or Salvinia), and a dark bottom. Intricate roots will offer reassuring refuges, promoting natural colors.

Diet and Feeding: Insectivore and micro-predator. Easy to feed: flakes, micro-pellets, and freeze-dried foods. To simulate the natural diet and induce reproduction, it is good to provide daphnia, cyclops, and bloodworms (live or frozen).

Water Quality: Intolerant to high nitrates and calcareous waters. Requires very soft (GH < 8) and acidic water (pH 5.5-6.5). A regular water change with RO and the addition of catappa extracts is strongly recommended.

Compatibility and Tankmates: Perfect for delicate community tanks. Excellent with Nannostomus, Carnegiella, small Loricariids, and Apistogramma. NEVER keep with aggressive fish or fish large enough to consider it prey (e.g. Pterophyllum).

Aquarium Reproduction: Pelagic egg scatterers (among plants). They spawn at dawn after intense male chases. Requires a sterile breeding aquarium, dark acidic water, and a bottom net, as parents are avid predators of their own eggs.

Risks and Diseases: In unsuitable waters (hard and alkaline) it undergoes constant osmotic stress, fading colors and becoming prey to skin fungi (Saprolegnia) and intestinal parasites.