Black-Winged Hatchetfish Care Guide - Setup, Feeding & Breeding

Black-Winged Hatchetfish are small, laterally compressed characins with a distinctive deep chest and an upswept body profile that resembles the blade of a hatchet. Their silvery, translucent sides are marked by a dark band and dusky to black areas across the fins and upper body, helping them disappear against broken reflections at the water’s surface.

These fish spend most of their time in the uppermost part of the aquarium, where their upturned mouths are well suited to taking food from the surface. They are alert but peaceful, and a group moving together beneath floating cover creates a lively natural focal point.

In nature, Black-Winged Hatchetfish live in calm, dimly lit waters beneath overhanging vegetation and forest canopy. Their powerful pectoral muscles and strongly developed fins allow them to leap from the water when startled, an adaptation that helps them escape predators but also makes them accomplished aquarium jumpers.

Carnegiella marthae is one of the smaller hatchetfish species and is best appreciated in a mature, gently flowing community aquarium. Its subtle markings become most attractive when the fish feel secure, particularly in a well-planted tank with shaded surface areas.

Black-Winged Hatchetfish are native to northern South America, particularly the Rio Negro and upper Orinoco drainage regions of Brazil, Colombia and Venezuela. They inhabit calm, shaded forest streams, tributaries and flooded-forest waters with soft, acidic conditions.

A group should have at least 60 litres of aquarium space, with a footprint around 60 × 30 cm or larger and a secure, tightly fitting lid. Use a dark, fine-grained substrate, subdued lighting, floating plants and taller vegetation or branches around the sides to create shade while leaving an open feeding area at the surface. Gentle filtration and a calm current suit their natural waters, and the aquarium should have very little open space between the waterline and cover because these fish can leap surprisingly high.

Up to about 4 cm (1.6 inches). Females are typically slightly deeper-bodied and fuller through the belly than males, while males are usually slimmer; overall length is broadly similar between the sexes.

Black-Winged Hatchetfish naturally feed on small insects and other invertebrates found at or just above the water’s surface. Offer a varied diet of quality floating flakes or micro-pellets supplemented with live or frozen foods such as fruit flies, mosquito larvae, daphnia and baby brine shrimp. Small floating foods are preferable, as sinking meals may be missed by these surface-feeding fish.

Black-Winged Hatchetfish are peaceful community fish suited to similarly gentle species such as small tetras, pencilfish, rasboras, peaceful Corydoras, small loricariid catfish and other calm South American fish. They should not be housed with large cichlids, predatory fish, boisterous feeders or persistent fin-nippers. Because they occupy the surface, tankmates that constantly harass or outcompete them at feeding time are particularly unsuitable.

Black-Winged Hatchetfish are rarely bred in home aquariums, but spawning may be encouraged with very soft, acidic water, subdued lighting and abundant live or frozen foods. They are egg scatterers that release eggs among fine-leaved plants or other cover, and the adults should be removed after spawning because they may eat the eggs. The eggs hatch in roughly a day, with free-swimming fry requiring tiny live foods such as infusoria before they can accept newly hatched brine shrimp.

Females generally have a rounder, deeper body, especially when carrying eggs, whereas males tend to remain slimmer. The difference is subtle and is easiest to see when mature fish are viewed from above.