Can hatchetfish live with black neon tetras?

Verdict
Yes

Yes, hatchetfish and black neon tetras can live together. Both are fine at 75–81°F. Plan on at least 20 gal.

HatchetfishHatchetfish75–81°F · pH 5.5–7.5 Black neon tetraBlack neon tetra73–81°F · pH 5.5–7.5

Why it works

Water side by side

55°60°65°70°75°80°85°90°Both: 75–81°Hatchetfish 75–81°Black neon tetra 73–81°
The green band is the temperature range both can live in.
456789Both: 5.5–7.5Hatchetfish 5.5–7.5Black neon tetra 5.5–7.5
The green band is the pH both tolerate.

Size to scale

Hatchetfish · 1.5 inBlack neon tetra · 1.5 in0"1"2"3"4"5"6"
Adult length in an aquarium. A fish can swallow anything that fits in its mouth, roughly a third to half its own length for predators.

Care at a glance

HatchetfishBlack neon tetra
Temperature75–81 °F73–81 °F
pH5.5–7.55.5–7.5
Adult size1.5 in1.5 in
Minimum tank20 gal15 gal
TemperamentPeacefulPeaceful
Swims atTopMiddle
GroupGroups of 6+Groups of 6+
DietCarnivoreOmnivore

Better tank mates for hatchetfish

All hatchetfish tank mates

Better tank mates for black neon tetras

All black neon tetra tank mates

Questions

Can hatchetfish live with black neon tetras?

Yes, hatchetfish and black neon tetras can live together. Both are fine at 75–81°F. Plan on at least 20 gal.

What temperature suits both hatchetfish and black neon tetras?

75–81 °F. Hatchetfish need 75–81 °F, black neon tetras need 73–81 °F.

What size tank do hatchetfish and black neon tetras need together?

At least 20 gal, set by the hatchetfish. Add space for each extra fish.