// Workers AI · dad joke modeWhat did Gasteropelecidae say? I'm a sucker for friends.

This article is about the freshwater hatchetfish of South and Central America. For the elongate hatchetfish from the same region, see Triportheus. For the marine fishes of the family Sternoptychidae, see marine hatchetfish.

Freshwater hatchetfish
Blackwinged hatchetfish (Carnegiella marthae)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
(unranked):	Otophysi
Order:	Characiformes
Suborder:	Characoidei
Family:	Gasteropelecidae Bleeker, 1859
Genera
See text

The freshwater hatchetfish are a family, Gasteropelecidae, of ray-finned fish from South and Central America. The common hatchetfish is the most popular member among fish keeping hobbyists. The family includes three genera: Carnegiella (four species), Gasteropelecus (three species), and Thoracocharax (two species).

Distribution and habitat

Freshwater hatchetfish originate from Panama and South America (though they are absent from Chile). They tend to be an upper-level fish, often swimming directly below the surface of the water, biding their time patiently.

Size

When fully grown, freshwater hatchetfish typically range in size from 1 to 2.5 inches (2.5 to 6.4 cm). One exception is the giant hatchetfish (Thoracocharax securis), which can grow up to 3.5 inches (8.9 cm). The smallest species are the pygmy hatchetfish (Carnegiella myersi), which only grows to about 0.9 inches (2.3 cm), and the dwarf hatchetfish (Carnegiella schereri), which grows to about 1 inch (2.5 cm).

Flight

The most obvious trait of the freshwater hatchetfish is their enormously enlarged sternal region. This is accompanied by large pectoral fins and "extraordinarily powerful" associated muscles which account for up to one-quarter of their total body weight. "Quick beats of the pectoral fins" allow hatchetfish to "lift themselves half out of the water and glide along the surface ... Some species can even leave the water for short stretches." Because of this ability to fly and tendency to jump, aquaria used to keep hatchetfish should have a tightly sealed cover to prevent these fish from escaping.

Genera

The genera in this family are:

• Carnegiella C. H. Eigenmann, 1909
• Gasteropelecus Scopoli, 1777
• Thoracocharax Fowler, 1907

Further reading

• "Gasteropelecidae". Integrated Taxonomic Information System.
• Froese, Rainer; Pauly, Daniel (eds.). "Family Gasteropelecidae". FishBase. October 2011 version.
• Nelson, Joseph S. (2006). Fishes of the World. John Wiley & Sons, Inc. ISBN 0-471-25031-7