Aduja's Tetra

Geographic Origin and Biotope: Middle and upper Rio Negro systems in Brazil. They populate slow watercourses (Igarapés) and "blackwater" oxbow lakes extremely poor in minerals, loaded with decomposing humic acids in the thick of the Amazon forest.

Taxonomy and Morphology: Red-line Iguanodectes (Iguanodectes adujai). Atypical characin with a very slender, cylindrical, and tapered "torpedo" body shape. Features a terminal mouth and a very long anal fin at the base.

Social Behavior: Very active pelagic species that never stops. Swims in very tight and compact schools against the current or hovering in mid-water. Absolutely peaceful and shy, needs schools (10+ specimens) to calm down.

Coloration and Sexual Dimorphism: Semi-diaphanous to silvery/greenish body. The distinguishing feature is a tricolor line (red, golden, black) that crosses the flank from the snout to the base of the caudal fin. Males slightly more intense and with a concave anal fin.

Aquarium Setup: Requires very long aquariums (minimum 100 cm / 40 inches in length). Essential to leave a huge amount of space for uninterrupted swimming. Set up the perimeter and bottom with twisted roots and a modest water current.

Diet and Feeding: Tends to be a pelagic carnivore/insectivore. Gathers food floating in the water column. Gladly eats fruit flies (Drosophila), frozen bloodworms, daphnia, and slow-sinking granules.

Water Quality: Very delicate regarding water chemistry. Only tolerates ultra-soft (GH 1-5) and distinctly acidic (pH 5.0-6.5) waters. Sensitive to fluctuations and nitrates: massive filtration is imperative.

Compatibility and Tankmates: Admirable and peaceful guest, coexists perfectly in large blackwater biotopes with Discus (as long as the temp does not exceed 28°C / 82°F), Apistogramma, and large schools of Corydoras sterbai or adolfoi.

Aquarium Reproduction: Extremely rare in captivity due to the ultra-acidic and pure water required for egg development. Spawns on mosses. The eggs are lucifugous (they degrade under strong lighting).

Risks and Diseases: The only pathologies are derived from osmotic shock or alkalosis. It is an excitable and jumping species: if the tank is uncovered and they are frightened, they will fatally jump out as a school.