Hatchetfish Species Profile

Hatchet Fish the flying fish of the aquarium

Few people are aware of the hatchetfish, a fascinating tiny freshwater flying fish. Similarly, many aquarists who keep these popular fish are unaware of their exceptional capacity to fly, especially given their small size. Hatchetfish fly lengthy, gliding flights over the top of the water in the wild, utilizing their strong "wing-like" fins. These stunning fish may be kept in a home aquarium but will not attempt to fly.

Species Overview

COMMON NAMES: Marbled hatchetfish

SCIENTIFIC NAME: Carnegiella strigata

ADULT SIZE: 1 to 1.4 inches



Family Gasteropelecidae
Origin Bolivia, Brazil, Peru, Columbia
Social Schoaling
Tank Level Top-dweller
Minimum Tank Size 30-gallon
Diet Insect larvae
Breeding Egg scatterer among surface roots
Care Intermediate to advanced 
pH 4.0 to 7.0
Hardness 4 to 2 dGH
Temperature 78 F to 82 F

Origin and Distribution

There are three species of hatchetfish in the genus Carnegiella: Carnegiella myersi, Carnegiella marthae, and Carnegiella strigata. Only Carnegiella strigata is widely recognized, and it is divided into at least five subspecies, all of which can be found in aquarium stores today.

The hatchetfish is found in the Guianas in northern South America, in marshes, flooded areas, brooks, ditches, and small and large rivers. It is particularly prevalent in the rainforest streams of the Amazon River basin's central and lower regions.

Hatchetfish live just beneath the water's surface, preferring to conceal amid marsh and water plants as well as raised roots. As they forage for larval insects and tiny aquatic invertebrates, they shoal together. When a larger fish comes close enough to eat them, the hatchetfish leap into the air and fly away from danger.

Colors and Markings

Hatchetfish are named for their unusual form. From the side, they resemble triangles with a rounded bottom, similar to the form of a hatchet. They're thinner than a cracker from the front, tapering to a wedged knife-edge down the belly. Large muscles contribute to the fish's capacity to flap its fins in flight due to its unusually deep body.

The fundamental colour of the marbled hatchetfish is brownish to golden yellow with a silver sheen; the back is dark green with variable sizes of black spots. The flanks are covered in a pattern of dots that range in hue from pink to brown to bright blue. A pair of dark stripes may be observed on the sides of the head, and a black lateral line extends from the gill covers to the caudal fin, bordered on the upper side by a shining silver stripe.

Three irregular dark blue to brownish-black lines angling forward and backward across the body run from the belly's edge. Above the anal fin, there is a blackish stripe. The fins are translucent and pale greenish. The caudal fin is a bright green color.


Hatchetfish are shoaling fish, meaning they prefer to be maintained in groups of at least ten. Any group skirmishes are only for fun, and there is never any harm done. They are quite tolerant of bottom dwellers and may be kept safely with fish of similar size that are quiet and mild-mannered.

Hatchetfish Habitat and Care

Captured wild hatchetfish will never try flight again after around 48 hours of failure. It's a shame we don't get to watch these fish fly in the tank, but they've been raised in captivity for so long that they've lost the drive to even try, even when frightened from below.

This fish only lives in blackwater settings. They enjoy fallen branches, living plants, and rock outcroppings, and they must have enough space to swim in and around them. Putting these unusual fish in an empty tank will make them feel vulnerable and uneasy, and they will not live for long.

Hatchetfish are a popular addition to aquariums, but keep in mind that they are forest-dwelling fish. Subdued or muted lighting is ideal for a big aquarium. To mimic their native environment, use plant species that grow up to the water's surface. To replicate the riverbed, use a dark substrate.

Although it is improbable that fish purchased in local markets and reared in captivity will attempt to fly, do not rule out the possibility. To minimize unexpected flights, every aquarium holding hatchetfish should be completely covered with a full aquarium hood.

Hatchetfish Diet and Feeding

They are bug and larva feeders in nature, consuming terrestrial and aquatic invertebrates as well as other zooplankton at or near the water's surface. They are quite efficient in reducing mosquito populations.

It will eat dry foods of a sufficient size in the aquarium, but it should also be fed tiny live and frozen foods such as nauplii, Daphnia, Moina, or grindal worms on a regular basis. Drosophila fruit flies or other juvenile insects that you can cultivate in bulk can also be fed to the fish, but it's preferable to fill their stomachs first (bio-loading) by feeding them fish flakes and vegetable debris.

Gender Differences

There are no known external sexual features. Adult females are prone to become bigger and fuller-bodied than other individuals. Color lines are slightly diverse, partially owing to inbreeding and partly depending to observing technique. All hatchetfish seem silver when they are not in perfect reproductive form or when they are not being observed attentively.

Breeding the Hatchetfish

Spawning is conceivable in this species, although it is uncommon. This is an extremely tough fish to breed, and only an expert breeder or someone looking for a challenge with the time, space, and patience to try should attempt it.

At the natural twilight of a tank lighted by natural sunlight, this species distributes its eggs among the high roots of plants quite near the water's surface. Spawning can also happen in the presence of artificial moonlight. Temperature is critical for spawning; 86F is the greatest match for their native environment in late spring/early summer.

Males do a fluttering dance parallel to females on the branches of finely feathered plants under the water's surface while spawning. These fine-leaved plants cling to the sticky dispersed eggs. It is not difficult to raise the fry, which hatch after 24-30 hours. Rotifers (infusoria) and later newborn brine shrimp should be fed to them.

Hatchetfish do not consume eggs, thus timing is less important than with many other tropical fish. Hatchetfish parents, on the other hand, will aggressively consume the fry as soon as they hatch, so remove them within 24 hours. Also, make sure that any plants used in a breeding tank are clear of snails, as snails love fish eggs.

More Pet Fish Species and Further Research

If hatchetfish appeal to you, and you are interested in some compatible fish for your aquarium, read up on:

Check out additional fish species profiles for more information on other  fish.