Common hatchetfish

Care at a glance

Overview

Keep them in a group of at least six, since they get jumpy and stressed alone. They sit at the top and rarely come down, so a tank around 125 liters or more with surface room suits them. Aim for the low to high 20s C and a pH on the acidic to neutral side. They are peaceful with calm tankmates and take small floating foods, flake, and tiny live or frozen insects.

In the wild

Common hatchetfish come from slow, shaded streams in the Amazon Basin, mostly around Brazil. The water there is soft, acidic, and stained brown with tannins, with leaf litter and overhanging plants up top. At home, give them a tight-fitting lid, some floating plants for cover, and gentle flow. They spend their whole life right at the surface, so the top of the tank matters most.

Good to know

This is a member of the Gasteropelecidae family, the freshwater hatchetfishes. Adults stay small, around 4 cm. They are egg scatterers with no recorded captive breeding success to speak of, and they get their name from the deep, keel-shaped chest that holds their oversized pectoral muscles.

Did you know

They can launch out of the water and beat their pectoral fins to skim across the surface, which is why a covered tank is not optional. In the wild this short burst helps them break away from a chasing predator.

Related species

• 

  Spotted hatchetfish

  Gasteropelecus maculatus

  3.5 in (9 cm)26 gal (100 L)73–82°F (23–28°C)

• 

  Marbled hatchetfish

  Carnegiella strigata

  1.6 in (4 cm)32 gal (120 L)68–82°F (20–28°C)

• 

  Blackwing hatchetfish

  Carnegiella marthae

  1.4 in (3.5 cm)30 gal (115 L)68–82°F (20–28°C)

• 

  Pygmy hatchetfish

  Carnegiella myersi

  1 in (2.5 cm)26 gal (100 L)73–79°F (23–26°C)

• 

  Spotfin hatchetfish

  Thoracocharax stellatus

  3.5 in (9 cm)26 gal (100 L)73–82°F (23–28°C)
• Red neon blue-eye

  Pseudomugil luminatus

  1.4 in (3.5 cm)11 gal (40 L)72–81°F (22–27°C)