Blackwing Hatchetfish

Carnegiella marthae, the Blackwing Hatchetfish, is a slender Carnegiella species characterised by the faint darkening of the pectoral fins and a crisp dark mid-lateral stripe on a silver-white body. It is native to blackwater tributaries of the Amazon system and closely related to the Marbled Hatchetfish, sharing the same surface-dwelling, jumping lifestyle.

Like its relatives, C. marthae demands a fully covered aquarium and soft acidic water to thrive long-term. It is somewhat less commonly available than C. strigata in the trade, making it a sought-after addition for hatchetfish enthusiasts. Groups of six or more settle quickly and display relaxed, natural behaviour.

Feeding at the surface with floating micro-pellets, wingless fruit flies, baby brine shrimp, and freeze-dried foods covers its nutritional requirements well. Regular small feedings are preferred over large infrequent meals, mimicking the continuous surface-feeding behaviour seen in the wild.

Water: 23–28°C, pH 5.0–6.8, soft (GH 1–10, KH 0–5); blackwater conditions recommended. Tank: 60 L minimum; tight lid essential; floating plants for cover; minimal surface current. Feeding: Floating micro-pellets, wingless fruit flies, baby brine shrimp, freeze-dried foods at surface. Breeding: Rarely achieved; soft acidic water required; egg-scatterer among surface plants. Compatibility: Peaceful with small-to-medium peaceful fish; avoid nippy or boisterous species.