Marbled hatchetfish (Carnegiella strigata) are from the Amazon River. They are small fish that reach an adult size of less than 2 inches (5 cm) in length. The common name of hatchetfish is due to the unusual shape of this fish. They belong to the family Gasteropelecidae. There are other species of hatchetfish and these have the same body shape as the marbled hatchetfish, but they have different markings and coloration. Their behavior and requirements are similar to the marbled hatchetfish.
Hatchetfish are peaceful fish and can be kept in a community tank. They don't like a lot of light and so you should have lots of plants in your tank. You should provide some floating plants too, such as hornwort. They swim mostly at the top level of the aquarium. They should be kept in a tightly covered aquarium because hatchetfish will often fly right out of the tank. In their natural environment they use their ability to jump out of the water to escape their predators. In the aquarium this is likely to land them onto the floor.
Like all fish from the Amazon, they prefer soft, slightly acidic water, and a water temperature between 76-82 degrees Fahrenheit or 20-25 degrees Celsius. They are shoaling fish and so you need to keep them in groups of 6-8. They don't survive long as solitary individuals.
They will eat flakes, frozen, freeze-dried, and live foods. They are omnivores, eating both meaty and plant based foods. In their natural habitat they typically feed on small insects and insect larvae.
Breeding Hatchetfish and Care of Fry
They are egglaying fish that will sometimes breed in the aquarium. The males are more colorful with more markings on them than the females. Spawning usually occurs among the plants.
The eggs will adhere to the plants and hatch in a little over a day. About 4-5 days later the fry will be free-swimming and must be fed. They are very small and so at first you should feed them infusoria or liquid commercial fry food for egglayers.
Once they are a little older you should feed them newly hatched brine shrimp. If you find hatching your own brine shrimp to be too cumbersome you can buy instant baby brine shrimp manufactured by Ocean Nutrition. Once the fry are old enough they can also be fed powdered fry food and/or crushed flakes.