In the world of science Silver Hatchetfish is renowned as Gasteropelecus Levis or Gasteropelecus sternicla. Commonly it is also known as Common Hatchetfish and River Hatchetfish other than the name of Silver Hatchetfish. Silver Hatchetfish is found in Brazil, South America and the southern tributaries of the Amazon. In Guyana and Surinam it is found in minor streams with plethora of vegetation.
Silver Hatchets, also known as the Common Hatchetfish, are among the more uniquely shaped species of fish. Hatchetfish have a slender body with a deep "belly" and pectoral fins that are set high on the body and attached to very powerful muscles. These fins 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].
These fish are avid jumpers and should have a well-covered tank, and during aquarium maintenance the tank should be covered as much as possible as they will take any advantage to jump out. Hatchetfish have upturned mouths characteristic of true surface dwellers.
Hatchetfish occur in slow flowing forest streams, usually thick with surface vegetation. It quickly jumps clear of the water when threatened from below, and probably also to catch flying insects. They live in large shoals, and should be maintained in groups of six or more fish. They are extremely peaceful and well suited to a community aquarium of small quiet fish like tetras and rasbora, discus, and dwarf cichlids.
The family Gasteropelecidae contains three genera. Thoracocharax, the mostprimitive and distinguished by its impressive keel, contains two species, T. securis and T. stellatus. Gasteropelecus contains two species, G. sternicla and G. maculatus, although G. levis is possibly a third species [Weitzman, 1996]. These two genera contain the largest of the hatchetfish, and all are silver in colouration; G. sternicla is the more frequently seen of these five species, though any of them are frequently offered as "Silver Hatchetfish." The third genus, Carnegiella, contains four species that 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.
Widely found throughout Amazon River basin, Peruvian Amazon, middle Amazon, the Guianas and Venezuela.
General Body Form:
Not your typical fish shape. The belly profile from the small ventral fins to the start of the tail fin is almost a straight line. The Dorsal profile is somewhat convex. The Dorsal fin itself is far back very close to the tail. The Pectoral (side) fins are half as long as the body, turned upward and face back which give them the look of wings. They have no Adipose fins.
This fish is not one of the most colorful fish, the base color of the fish is Silver with hints of Yellow or Green. Starting near the gills there is a long stripe that extends to the base of the tail fin, it is also yellow or green in color. The fins are transparent with a slight Golden hue to them.
6 cm / 2.5 inches. A tank of at least 20 gallons is preferred because of their size. They will stay at the top to medium level in your aquarium. So the bigger surface area the better.
Origin: The Amazon River Basin, the Guianas and Venezuela.
Size - Weight:
These fish get up to 2.5 inches (6.5 cm).
Care and feeding:
With their mouth situated up on top of their body you can see they must be used to eating surface foods such as small vinegar flies and mosquito larvae. In the aquarium the Common Hatchetfish will generally eat all kinds of live, fresh and flake foods as long as it is on the surface of the water. To keep a good balance give them a protein such as brine shrimp (either live or frozen), fruit flies, or blood worms everyday.
Top, Middle, Bottom: The Common Hatchetfish will swim at the top of the aquarium. Notice how the mouth is at the top of the body.
The Silver Hatchetfish (Gasteropelecus Sternicla) is suitable for community aquariums with other peaceful species. They are also schooling fish and will be much happier in a group of 6 or more. The large group will keep them less stressed, therefore less likely to get a disease.
Acceptable Water Conditions:
Hardness: 2-15° dGH
Ph: 6.0 to 7.0
Temp: 26-28° C
Sexing: Not easy, females slightly plumper
Breeding/Reproduction: The Common Hatchetfish are egg layers, but they have not been successfully bred in captivity.