Nego Dagua Tetra (Hyphessobrycon negodagua)

The Nego Dagua Tetra is a rare and striking species of tetra native to Brazil. Also known as the Bahia Black Diamond Tetra, this small, peaceful fish is a newer addition to the aquarium hobby and stands out for its dark, elegant coloration and smooth schooling behavior.

In the wild, Nego Dagua Tetras inhabit the calm, tannin-stained streams and tributaries of the Rio Paraguaçu system in the Bahia region of northeastern Brazil. These waters are soft, slightly acidic, and shaded by dense vegetation. The species name “negodagua” comes from a local legend about a mysterious river creature called “Nego d’água.”

Nego Dagua Tetras stay small, usually growing to about 1.2 to 1.4 inches in length. Males tend to be darker, sometimes appearing almost black with a subtle iridescent sheen and white-edged fins, especially when in breeding condition. Females are slightly rounder and paler. They are peaceful and thrive when kept in groups of six or more, where their natural schooling behavior can be fully appreciated.

For aquarium care, a minimum tank size of 20 gallons is recommended. They prefer soft, slightly acidic water with a pH between 5.5 and 7.0 and a temperature range of 75 to 82°F. A setup that mimics their natural habitat works best—plenty of live plants, driftwood, leaf litter, and subdued lighting. Good filtration is important, but strong currents should be avoided.

Nego Dagua Tetras are omnivorous and will readily accept quality flake or micro-pellet foods. To enhance their coloration and vitality, offer small live or frozen foods such as brine shrimp, daphnia, or bloodworms as part of their diet. Feed small portions one or two times a day.

These tetras do well in peaceful community tanks with other small, calm fish like rasboras, dwarf corydoras, or small tetras that prefer similar water conditions. Avoid housing them with large, aggressive, or fin-nipping species.

Breeding Nego Dagua Tetras in captivity is not yet well documented. Like most small tetras, they are likely egg scatterers, depositing eggs among fine plants or spawning mops. Adults may eat the eggs, so separating the breeders afterward is advised if spawning is attempted.

The Nego Dagua Tetra’s dark, sleek appearance makes it a beautiful contrast to brightly colored tankmates and green plants. Peaceful, active, and graceful, this species is ideal for aquarists who enjoy keeping unique and lesser-known tetras. With clean water, stable parameters, and a well-planted tank, the Nego Dagua Tetra will thrive and become a subtle yet captivating highlight in any freshwater aquarium.