Blackwing hatchetfish

Care at a glance

Overview

Keep at least six together in a tank of roughly 115 liters with plenty of surface area, and always use a tight lid. They sit right at the top and eat from the surface, so offer floating flake, small frozen foods, and live items like fruit flies or mosquito larvae. Keep them warm in the mid 20s C with soft, acidic to neutral water. They're peaceful and best with calm tankmates.

In the wild

Blackwing hatchetfish live in slow tributaries and floodplain pools of the Amazon, mostly in Brazil and Venezuela. The water is soft, acidic, and stained dark with tannins, with floating plants and roots up top where these fish stay. They want surface cover and very still water, so floating plants and a gentle filter outflow help a lot.

Good to know

This is a small hatchetfish in the family Gasteropelecidae, reaching about 3.5 cm. The deep, keel-shaped chest houses the muscles that power its oversized pectoral fins. Captive breeding is rarely recorded. The IUCN lists it as Least Concern.

Did you know

Hatchetfish are true flyers, not gliders. They beat those wing-like pectoral fins fast enough to break the surface and travel a short distance through the air, usually to escape something chasing them. That's exactly why a lid is non-negotiable.

Related species

• 

  Marbled hatchetfish

  Carnegiella strigata

  1.6 in (4 cm)32 gal (120 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)

• 

  Common hatchetfish

  Gasteropelecus sternicla

  1.6 in (4 cm)33 gal (125 L)68–82°F (20–28°C)

• 

  Spotfin hatchetfish

  Thoracocharax stellatus

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

• 

  Spotted hatchetfish

  Gasteropelecus maculatus

  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)