Vilma's Tetra

Geographic Origin and Biotope: Endemic to the upper Tapajós River basin (Mato Grosso, Brazil). Inhabits small shaded forest tributaries, where the water flows slowly and cleanly over a bed of soft sand and abundant dry leaf litter.

Taxonomy and Morphology: Hyphessobrycon vilmae. Dedicated to Vilma Géry (wife of ichthyologist Jacques Géry). Small tapered and compact characin, related to the H. agulha group, distinguishable by the possession of a sharp lateral dark line contrast.

Social Behavior: Very peaceful and social. Absolutely requires being kept in schools of at least 8-10 individuals to temper the natural propensity to hide in the presence of threats or in new environments.

Coloration and Sexual Dimorphism: Bright silvery background coloration with bluish reflections. The flank is marked by a marked horizontal black band topped by a thin iridescent golden stripe. Females have a more pronounced belly compared to the slender males.

Aquarium Setup: Min. 60 cm (24 inches) aquarium. Ideal a flooded forest biotope: low lighting filtered by floating plants (e.g. Phyllanthus fluitans), intricate roots, and a layer of Catappa leaves on the bottom to slightly amber the water.

Diet and Feeding: Insectivorous micro-predator. Adapts to flake food but given the tiny mouth it is necessary to frequently administer brine shrimp nauplii, micro-worms, and small daphnia to condition it in health.

Water Quality: Sensitive to nitrogen accumulations. Requires very soft (GH < 10) and acidic (pH around 6.0) water. The constant release of humic substances and tannins helps it prevent skin bacterial pathologies.

Compatibility and Tankmates: Vulnerable towards medium-large fish. Perfect tenant of nano community aquariums: pairs beautifully with small Corydoras (hastatus or pygmaeus), Otocinclus, and reassures small dwarf Cichlids (Apistogramma).

Aquarium Reproduction: Occurs by egg scattering at dawn among fine mosses or roots. The parents, if not removed promptly, will consume the entire brood in a short time. Fry require infusoria and pristine water.

Risks and Diseases: Very hardy if kept in the right parameters. Decidedly susceptible to immune stress if kept in solitude or in excessively alkaline and oxygen-poor waters.