Phoenix Tetra

Geographic Origin and Biotope: Rare endemism of the Araguaia River basin in Brazil. Inhabits shallow water bodies surrounded by grasslands, flooded oxbows, and small tributaries characterized by dense floating and marginal vegetation.

Taxonomy and Morphology: Phoenix Tetra (Hemigrammus filamentosus). Recently discovered (2011). The distinctive morphological feature, unique in the genus, is the extreme filament-like elongation of the first rays of the anal and dorsal fins.

Social Behavior: Very active, lively, and strongly gregarious. Males engage in frequent exhibitionist displays by extending their long fin filaments to intimidate rivals or court. Must strictly be kept in large schools (10+).

Coloration and Sexual Dimorphism: The name "Phoenix Tetra" derives from the dazzling flame-red color of the dorsal, anal, and caudal fins of dominant males, enhanced by the long white filaments. Females are less colorful, lack long filaments, and are plumper.

Aquarium Setup: Long tank (at least 80 cm / 32 inches for rapid horizontal swimming). The aesthetics of the fish are maximized with dark backgrounds, lateral or dimmed lighting from floating plants, and abundant vegetation (Myriophyllum, Cabomba) on the sides.

Diet and Feeding: Flexible omnivore. Quickly adapts to dry flake or micro-pellet foods. However, the glowing "phoenix" colors will only emerge by regularly offering Daphnia, brine shrimp, and frozen bloodworms.

Water Quality: Not particularly demanding like other rare Characins, but prefers weakly acidic and soft waters. Good water circulation with adequate oxygenation will simulate Amazonian rains.

Compatibility and Tankmates: Peaceful, but the long filaments of the males are an irresistible target for "fin nipper" fish (e.g. Tiger Barbs). Coexists well with other Tetras, rasboras, and Loricariids, provided they do not nip their fins.

Aquarium Reproduction: Males furiously chase females among fine-leaved plants. The tiny, non-adhesive eggs fall to the bottom. The use of a spawning net or synthetic mop and prompt removal of parents are essential.

Risks and Diseases: Deterioration of the delicate fin filaments is the first sign of water stress or overcrowding. Fungal infections can quickly attack injured fin rays.