Black Tetra

Physical Characteristics

Distinctive deep, laterally compressed body. Characterized by two vertical black bars on the front of the body and a large, black dorsal and anal fin that gives the fish a 'skirted' appearance. Juveniles are jet black, while adults may fade to a smoky grey.

Habitat & Distribution

Native to the Paraguay and Guaporé River basins in South America (Brazil, Paraguay, Argentina). Prefers slow-moving rivers, creeks, and subtropical tributaries with plenty of vegetation and overhead cover.

Size & Weight

Typically reaches an adult length of 5–6 centimeters (2–2.5 inches). Weight is negligible, usually just a few grams.

Similar Looking Species

Black Phantom Tetra (Hyphessobrycon megalopterus) which has a more elongated body and different fin shapes, and the Serpae Tetra which has more reddish coloration.

Ecological Role

Omnivorus species feeding on small crustaceans, insects, and worms. Plays a role as both a low-level predator of micro-invertebrates and prey for larger river predators. Currently listed as Least Concern by many regional assessments, though not globally evaluated by the IUCN.

Identified on: 2/18/2026

Mode: Standard