HomeFreshwater aquarium fishTetras & characinsBlackwing hatchetfish Blackwing hatchetfish (Carnegiella marthae) Scientific name: Carnegiella marthae Myers, 1927 The Blackwing hatchetfish (Carnegiella marthae) is a freshwater fish of the family Gasteropelecidae that grows to about 3.5 cm (1.4 in). It is easy to keep and peaceful, suits community aquariums and needs a tank of at least 75 L (20 US gal), water at 24–29°C (75–84°F) and a pH of 5.5–7.0. Native range: South America, forest streams in the Orinoco regoin. Blackwing hatchetfish care at a glanceCare levelEasyTemperamentPeacefulCommunity tankGoodAdult size3.5 cm (1.4 in)Minimum tank75 L (20 US gal)Temperature24–29°C (75–84°F)pH5.5–7.0Hardness1–8 dGH (18–143 ppm)DietOmnivore. Accepts flakes, frozen foods and live foods. BiologyFeeds mainly at the surface on insects, but also takes crustaceans. Aquarium specimens reach 3.5 cm TL.Source: FishBase, licensed CC BY-NC 4.0. Species factsScientific nameCarnegiella marthaeFamilyGasteropelecidae (Freshwater hatchetfishes)OrderCharaciformes (Characins)ClassActinopterygii (Ray-finned fishes)Maximum length2.8EnvironmentFreshwater;; pH range: 5.5 - 6.5; dH range: ? - 4 pelagicClimateTropicalDistributionSouth America: Negro and upper Orinoco River basins.Conservation status (IUCN)Not EvaluatedThreat to humansHarmlessUsesAquarium: commercial More tetras & characinsMarbled hatchetfishCarnegiella strigataRedspotted tetraCopeina guttataRiver hatchetfishGasteropelecus sterniclaBlackline penguinfishThayeria boehlkeiGolden pencilfishNannostomus beckfordiBarred pencilfishNannostomus espeiSee all tetras & characins SourcesTaxonomy, distribution and biology data: FishBase (Froese, R. and D. Pauly, eds.), licensed CC BY-NC 4.0. Aquarium care parameters compiled, checked and converted to metric and imperial units by Guppies.za.net.Last updated 28 September 2026