Freshwater hatchetfish

"This articles is about the freshwater hatchetfishes of the Amazon; for the marine fishes of the family Sternoptychidae, see the article on marine hatchetfish."

Taxobox
name = Freshwater hatchetfishes


image_caption = Blackwinged hatchetfish, "Carnegiella marthae"
image_width = 300px
regnum = Animalia
phylum = Chordata
classis = Actinopterygii
ordo = Characiformes
superfamilia = Characoidea
familia = "Gasteropelecidae"
subdivision_ranks = Genera
subdivision = "Carnegiella"
"Gasteropelecus"
"Thoracocharax"

The freshwater hatchetfishes are a family, Gasteropelecidae, of ray-finned fish. The common hatchetfish is the most popular member among fish keeping hobbyists. The family includes three genera: Carnegiella (4 species), Gasteropelecus (3 species), and Thoracocharax (2 species).

Distribution and habitat

Freshwater hatchetfishes originate from Panama and South America (though it is absent in Chile). They tend to be an upper-level fish, often swimming directly below the surface of the water.

Flight

The most obvious trait of the freshwater hatchetfish is their enormously enlarged sternal region. This is accompanied by large pectoral fins and massive associated muscles. Due to this, they are the only fish technically enabled for powered (as opposed to gliding, as in flyingfish) flight, although the exact degree to which this mechanism is actually used is not well researched. They can propel themselves out of the water and at least assist their flight by rapidly striking their pectoral fins to evade predators, albeit only for distances of a few meters and in a straight line. Alternatively, they can make shorter flying jumps to catch insects. Because of this ability to "fly", or at least this tendency to jump, when kept in an aquarium the cover should be tight and sealed to prevent these fish from escaping.

Genera and species

* Genus Carnegiella (Eigenmann, 1909)
** Blackwinged hatchetfish, "Carnegiella marthae"
** Pygmy hatchetfish, "Carnegiella myersi"
** Dwarf hatchetfish, "Carnegiella schereri"
** Marbled hatchetfish, "Carnegiella strigata"
* Genus Gasteropelecus (Scopoli, 1777)
** Silver hatchetfish, "Gasteropelecus levis"
** Spotted hatchetfish, "Gasteropelecus maculatus"
** Common hatchetfish, "Gasteropelecus sternicla"
* Genus Thoracocharax (Fowler, 1907)
** Greater hatchetfish, "Thoracocharax securis"
** Spotfin hatchetfish, "Thoracocharax stellatus"

References

*
*
* Nelson, Joseph S. (2006). "Fishes of the World". John Wiley & Sons, Inc. ISBN 0471250317