Agulha Tetra

Geographic Origin and Biotope: Originating from the Madeira River basin (Brazil and Bolivia). Frequents shady forest ponds, flooded oxbows, and slow-flowing minor streams, among a dense carpet of dead leaves and amber water.

Taxonomy and Morphology: Agulha Tetra / Red-tailed Tetra (Hyphessobrycon agulha). Discovered by Fowler in 1913. Compact shape, similar to its cousins of the Hyphessobrycon genus, with a small forward-facing mouth, suitable for pelagic micro-predation.

Social Behavior: Peaceful, slightly shy. Needs the security of a group (at least 8 specimens) to actively explore the tank; in small numbers, it nervously holes up among the vegetation on the bottom.

Coloration and Sexual Dimorphism: Very fascinating livery: lower half of the body golden/coppery and upper part silvery. A very distinct horizontal black band runs along the flanks and ends on the caudal peduncle, bordered with bright red. Males are slimmer and more colorful.

Aquarium Setup: 60-80 cm (24-32 inches) aquarium, set up in Amazonian style. Soft light (shielded by Pistia or duckweed), dark sand or soil, lots of Mopani wood and branches. Peat filtration highly suggested.

Diet and Feeding: Omnivore (Micro-predator). Feeds easily. Administer high-quality dry food enriched to enhance red colors, systematically integrating it with live or frozen food (brine shrimp nauplii, daphnia, cyclops).

Water Quality: Prefers soft and moderately acidic waters (pH 5.5-7.0) with GH between 1 and 10. Stable temperature between 22 and 27°C (72-80°F). A high tannin load in the water is appreciated and contributes to its well-being.

Compatibility and Tankmates: Perfect for peaceful community tanks. Tolerates quiet tankmates: Corydoras, Otocinclus, small dwarf Cichlids (e.g. Dicrossus), and other South American Characidae. Frenetic fish will inhibit it.

Aquarium Reproduction: Scatters non-adhesive eggs at dawn among dense tufts of moss. To save the brood from the parents, a dedicated tank with a bottom grid must be used for the eggs to fall through, darkening the glass until hatching.

Risks and Diseases: Deterioration of water values (nitrate accumulation) instantly dims its brilliant colors and makes it subject to bacterial conditions. Regular but small water changes are necessary.