Gasteropelecidae Common Name:
Pygmy Hatchetfish Origin and Habitat
: Peruvian Amazon basin. A second population is known from Bolivia. Found in small, shaded and shallow woodland streams in the forest. Compatibility/Temperament:
Extremely peaceful shoaling fish, must be in a group of at least six but preferably more. Should not have active tankmates; small, peaceful characins, dwarf cichlids, small catfish and loaches, rasbora are suitable. Pygmy Hatchetfish Diet
Insectivore by nature, eating small insects on the water surface, it will usually accept most prepared foods that float such as flake and small dried insects and bloodworms. Wingless fruit flies are ideal as a live treat. Size
Maximum 1 inch. Minimum Tank Suggestion
20 inches in length; the surface area is more important than volume. Water parameters for Pygmy Hatchetfish
Soft (hardness below 5 dGH) acidic (pH up to 6.6, preferably below 6) water, temperature 23-26C/73-79F. As all fish will be wild-caught and are delicate, care must be paid to the water parameters. Description
The smallest and most delicate of the known hatchetfishes. The rounded keel is shallower than all other hatchetfish species, giving this fish it's distinctive longer profile. The large pectoral fins are attached by powerful muscles that propel the fish from the water, enabling it to glide considerable distances through the air. Studies by Francine Weist (1995) concluded that the pectoral fins are not moved during this "flight" but are used as a powerful thruster to propel the fish from the water as well as to prevent the fish from diving too deeply upon its return to the water [reported in Weitzman & Palmer, TFH, September 1996].
This species requires a well-matured aquarium with floating plants but providing some clear surface for swimming, very little water movement, and dim lighting. The top must be well covered; like all hatchetfish, this one will readily jump whether through play or interaction within the group, fright from other fish below, or if disturbed even by sliding the cover open for feeding. There are no external gender differences; females are rounder when viewed from above.
The species in Carnegiella
are the smallest of the hatchetfishes. The subject species, along with C. marthae
and C. schereri
, are basic silver with varying darker dots, dashes or lines across the keel. The Marble Hatchetfish
, C. strigata
is the fourth species in the genus. All these species are included in our profiles.
Described by Fernandez-Yepez in 1950 and named in honour of Dr. George S. Meyers, the American ichthyologist who did considerable early work in this genus. Sometimes may be seen under the common name "Levi's hatchetfish" but this should not be confused with a much larger fish seen under the name Gasteropelecus levis
which is a different and significantly larger and deeper-bodied hatchetfish somewhat rare in the hobby.
The family Gasteropelecidae contains three genera: Thoracocharax
with two species, Gasteropelecus
also with two species [G. levis
is possibly a third species (Weitzman, 1996)] and the four recognized species in Carnegiella
; the latter are the most derived or specialized of the hatchetfishes. Weitzman & Palmer hypothesize on the basis of their anatomy that these three genera had a common ancestor in the distant past that was related to some other characiform subgroup, making this family monophyletic. The species in Carnegiella
do not possess an adipose fin. References:
Weitzman, Stanley H. and Lisa Palmer (1996), "Do Freshwater Hatchetfishes Really Fly," Tropical Fish Hobbyist
, September 1996, pp. 195-206.
Weitzman, Stanley H. and Lisa Palmer (2003), "Family Gasteropelecidae" in Checklist of the Freshwater Fishes of Central and South America
, ed. Roberto E. Reis, Sven O. Kullander and Carl J. Ferraris; Porto Alegre: Edipucrs, pp. 101-103.
Wiest, F.C. (1995), "The specialized locomotory apparatus of the freshwater hatchetfish family Gasteropelecidae," Journal of Zoology
, No. 236, pp. 571-592. Contributing Members
The following members have contributed to this profile: Byron