Care Guide for Hatchetfish – Oddball Schooling Fish with Wings

Most freshwater fish like to hang out in the lower two-thirds of the aquarium, so it can be hard to fill in the upper third with some activity. The hatchetfish is here. The top-dwelling, nano fish is unique in its appearance. There are large schools of them swimming just below the water surface. However, they have some special care requirements to be aware of, so let’s take a closer look at this interesting oddball.

What are Hatchetfish?

The freshwater hatchetfish are part of the Gasteropelecidae Family and are distantly related with tetras. They can be found all over South and Central America and are known for having a hatchet-shaped body and pectoral fins that extend out from the body like bird wings. The hatchetfish’s strong pectoral muscles allow them to leap several inches above the water and escape predators quickly.

What types of hatchet fish are available? There are many species that are available at your local fish store, though they may not be in stock. They usually range from 1-2.5 inches (2.5-6 cm) long, so we have listed them roughly in order of smallest to biggest size.

– Pygmy hatchetfish (Carnegiella myersi) – Blackwing hatchetfish (Carnegiella marthae) – Marbled hatchetfish (Carnegiella strigata) – Silver hatchetfish (Gasteropelecus levis) – Common hatchetfish (Gasteropelecus sternicla) – Spotted hatchetfish (Gasteropelecus maculatus) – Platinum or spotfin hatchetfish (Thoracocharax stellatus)

Marbled hatchetfish (Carnegiella strigata)

Although some species, like the common hatchetfish can be kept in tanks or cages, many hatchetfishes were caught wild. By the time they travel from the wholesaler to the fish store, they may be underfed with weakened immune systems, making them more susceptible to disease. Before making a purchase, ask the fish shop how long they have had the hatchetfish. Also, observe how they eat and their behavior.

We strongly recommend that you always quarantine hatchetfish, feed them lots of high-quality foods, and proactively treat them with the trio of quarantine medications if possible. Hatchetfish are prone to ich or white spot disease, which is easily cured with Aquarium Solutions Ich-X. Wild-caught fish can also be affected by internal parasites such as tapeworms. To eliminate these parasites, treat them with Fritz ParaCleanse, and then again two weeks later.

How to Set Up an Aquarium for Hatchetfish

Because they live in areas that experience flooding and rainy seasons every year, the pH, GH and other parameters of water can be varied for Hatchetfish. They are tropical animals and can thrive at temperatures between 75-80degF (24-25 degC). As a schooling fish, they need to be in a big group of at least 6-12 fish of the same species. They feel safer and more comfortable displaying their natural behavior when there are more fish in their school. Cory McElroy was once the CEO of a group that included 30 silver hatchetfish. He would notice a bright flash of light when their scales were reflecting like mirrors as they switched directions.

A school of hatchetfish in a blackwater aquarium

Hatchetfish are not super active, so you can keep them in a 20-gallon aquarium or larger. The tank needs a tight-fitting lid. Hatchetfish will jump out from the narrowest slots they can find. If you have any openings for the filter, heater, or automatic fish food feeder, make sure to cover them with craft mesh or another material.

What fish can live with hatchet fish? Avoid keeping hatchetfish with other fish that are aggressive, large enough to eat them, or fast-swimming and able to outcompete them for food. They do best with tank mates that are similar-sized and peaceful, such as tetras and corydoras catfish. South American dwarf cichlids like German blue rams and Apistogramma cichlids are also fine because they occupy the lower half of the tank, while hatchetfish stay up above.

What Do Hatchetfish Eat?

Fishkeepers face a problem with hatchetfish as they grow larger. They need to feed them properly because hatchetfish prefer to eat on the surface of the water and don’t like to swim down for sinking food. In the wild, they use their small, upward-facing mouths to feed on insects and zooplankton. To ensure that the food doesn’t sink too quickly, you should give them tiny foods that float. Good floating foods include high-quality flakes, floating pellets, freeze-dried foods, and live baby brine shrimp that tend to swim toward the aquarium light.

Platinum hatchetfish (Thoracocharax stellatus)

We hope that you enjoy the hatchetfish’s unusual appearance and behavior. For more ideas on other surface dwellers to try, check out our article on the 10 Best Top-Dwelling Fish for Your Aquarium.