About the Marble Hatchetfish
Species Type: Freshwater Fish
Care Level: Moderate. May tolerate only a narrow range of water parameters, have specific dietary requirements including frozen or even live foods, may have behaviors that severely limit potential tankmates or may require a specialized aquarium setup.
Origin: South America: Columbia, Guyana, Suriname, Peru and Brazil. Occurs in small forest streams usually with surface vegetation.
Compatibility/Temperament: Very peaceful; must be kept in groups of at least six and preferably more. Can be combined with other species of the genus, and small peaceful fish such as tetras, rasbora, dwarf cichlids, discus, small catfish and loaches.
The hatchetfishes are surface fish identified by their rounded keel. 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].
The aquarium must be well covered, and careful attention during maintenance is necessary as the fish will quickly jump if alarmed or frightened. Suitable only for aquaria of small, peaceful fish. Must have floating plants. Newly-imported fish are very sensitive and must be carefully acclimated but once established they are hardy. Very prone to ich during shipment or when under stress. Does not do well in water that is not soft and acidic.
Best suited to an aquarium with minimal surface movement; in larger aquaria when given the option of areas with surface movement from the filter or still water, the fish invariably chooses the latter. It's origin in streams with surface vegetation is an indicator of minimal water movement.
This species has a varied pattern depending upon its origin location; this is illustrated in the accompanying photo which shows two fish with a significantly-different mid band across the keel. At one time or another, five species were recognized, reorganized into two by Weitzman in 1960, C. strigata and C. vesca. Gery (1977) modified these as C. strigata strigata and C. strigata fasciata respectively, and these were then combined by Weitzman & Palmer in Reis, et al. (2003) into the presently recognized single species C. strigata.
The species in Carnegiella are the smallest of the hatchetfishes; none posses an adipose fin. The other species in the genus are Carnegiella marthae [Meyers, 1927], C. schereri [Fernandez-Yepez 1950], and C. myersi [Fernandez-Yepez, 1950], the smallest species.
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.
Marble Hatchetfish Diet
Feeds primarily on insects that are on or land on the water surface. Will accept prepared foods that are small and float such as flakes and freeze-dried bloodworms. Insects such as wingless fruit flies are ideal.
Attains 1.5 inches.
Minimum Tank Suggestion
18 inches in length
Ideal water parameters for Marble Hatchetfish
Soft (hardness to 20 dGH) acidic to slightly basic (pH up to 7.5) water, temperature 24-28C/75-82F.