Carnegiella strigata

Hatchetfish

Gasteropelecidae is a family neotropical, keel-chested flying fish consisting of three Genera: Carnegiella, Gasteropelecus, and Thoracocharax. All are endemic to Central and South America, species within the Thoracocharx genus having the wdest range. Their distinctive, “hatchet” shape is due to the manner in which massive pectoral fin muscles, which comprise as much as 25% of their body weight, are attached to an extraordinarily deep sternum. It is this musculature that enables hatchetfish to leap from the water and glide for considerable distances on rigid, wing-like pectoral fins. The keel shape aides in stabilization and guiding upon returning to the water. Their unusual attributes also account for the hatchetfish’s considerable agility in evasion of preditors, when startled or in the pursuit of small prey.

Another distinguishing feature of hatchetfish is the up-turned mouth, which is well-suited for surface feeding. In the wild, hatchetfish are carnivors, eating primarily flying/terrestrial insects that either land in the water or fly close to its surface, mosquito and other surface-dwelling larvae, small crustaceans and fry.

Gregarious, although often quarrelsome with each other, hatchetfish are most comfortable in groups. 6 or more is best, and like most South American Characins, warm, soft, acid water conditions (pH 6.0-6.8, 72-82 degrees F) are preferable.

I am currently keeping C. strigata and G. maculatus.

Carnegiella strigata
Marbled Hatchetfish
Günther, 1864

Distribution:  Widely ranging throughout the Amazon drainages system and its tribuataries.
Size:  1.4″ (3.56cm)

Carnegiella strigata

Gasteropelecus maculatus
Spotted Hatchefish
Steindachner, 1879

Distribution:  Central and South America, from the Pacific slopes of Panama, throughout Pacific and Atlantic drainages of Colombia to the Maracaibo basin of Venezuela.
Size:  3.5″ (8.9cm)

Spotted hatchet fish, large as hatchets go, are quite striking.   I also find them to be quarrelsome and territorial.   Unlike the marbled and silver hatchetfish, they do not tend to congregate.  At least not in my aquarium.   Six of a group of 10 are pictured together in the anomalous shots above.  Taken shortly after introduction into a  very heavily-planted 125 gallon aquarium (just over 473 liters), each hatchetfish soon staked out territory, continually and aggressively clearing it of congeners, while demonstrating varying degrees of patience with other tank mates.  And although their shape suggests surface-dwelling habits,  I find that they spend more time swimming throughout the plants and branches of the aquarium than they do at the surface and tend equally toward pelagic and surface feeding.  Speaking of feeding… they are vigorous feeders.  So vigorous that care must be taken during feeding, as I have had “jumpers” when opening the aquarium lid.