Buenos Aires Tetra (Hyphessobrycon anisitsi)

Hyphessobrycon anisitsi, the Buenos Aires Tetra, is a robust and energetic tetra from the La Plata River basin in Argentina, Brazil, Paraguay, and Uruguay. Its common name references Buenos Aires, the Argentine capital, near whose river system this species was originally collected and described.

The Buenos Aires Tetra is notably larger and more boisterous than many popular tetra species, reaching 7–8 cm. The body is bright silver with a small black shoulder humeral spot and vivid red colouration in the fins, particularly the caudal and dorsal fins. The red fin colouration is particularly vivid in males and in well-fed specimens.

This species has a justified reputation for being a significant fin-nipper — even more pronounced than Tiger Barbs in some circumstances. When kept in small numbers (fewer than eight), they direct their energy toward other fish's fins. In groups of eight or more, intra-group interaction dominates and fin-nipping of other species is substantially reduced.

The Buenos Aires Tetra is cold-tolerant, thriving in the 16–28°C range that reflects its origin in the temperate-subtropical La Plata basin. It is suitable for cooler community setups and is notably more robust than many tropical tetras.

One significant consideration: this species is a prolific plant-eater. Soft-leaved aquatic plants will be consumed rapidly. Plant-only tank enthusiasts should choose a different species. Use tough, robust plants or avoid live plants entirely.

Tank Setup: A minimum 100-litre aquarium for a school of eight. Moderate to strong water flow. Open swimming space. Hardy, tough plants only (Java fern, Anubias, Vallisneria) — or no live plants. Alternatively, use artificial plants. Good filtration.

Water Parameters: Temperature 16–28°C; pH 5.5–8.5; GH 5–20 °dH; KH 3–15 °dH. Exceptionally adaptable. Cold tolerant — suitable for unheated aquariums in mild climates.

Feeding: Omnivore with herbivore tendencies. Accepts flake, pellets, all frozen foods, and will eat live and artificial plants. Supplement spirulina-based foods to reduce plant-eating behaviour. Feed two to three times daily.

Tank Mates: Keep with robust, fast-moving fish of similar or larger size: barbs, danios, larger tetras, corydoras, loaches, and rainbowfish. Avoid long-finned fish (Bettas, Angelfish, Guppies), small nano fish, and soft-leaved plants.

Behaviour: Active, fast-swimming schooling fish. Groups of 8+ reduce fin-nipping tendency significantly. Highly competitive at feeding time. Cold tolerant makes them unusual among tropical tetras.

Health: Exceptionally hardy. One of the most disease-resistant tetras. Tolerates a very wide range of parameters. Weekly 25% water changes recommended.