Can ember tetras live with hatchetfish?

Verdict
Yes

Yes. Ember tetras and hatchetfish make a good pair. Both are fine at 75–81°F. Plan on at least 20 gal.

Ember tetraEmber tetra73–84°F · pH 5.5–7 HatchetfishHatchetfish75–81°F · pH 5.5–7.5

Why it works

Water side by side

55°60°65°70°75°80°85°90°Both: 75–81°Ember tetra 73–84°Hatchetfish 75–81°
The green band is the temperature range both can live in.
456789Both: 5.5–7Ember tetra 5.5–7Hatchetfish 5.5–7.5
The green band is the pH both tolerate.

Size to scale

Ember tetra · 0.8 inHatchetfish · 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

Ember tetraHatchetfish
Temperature73–84 °F75–81 °F
pH5.5–75.5–7.5
Adult size0.8 in1.5 in
Minimum tank5 gal20 gal
TemperamentPeacefulPeaceful
Swims atMiddleTop
GroupGroups of 6+Groups of 6+
DietOmnivoreCarnivore

Better tank mates for ember tetras

All ember tetra tank mates

Better tank mates for hatchetfish

All hatchetfish tank mates

Questions

Can ember tetras live with hatchetfish?

Yes. Ember tetras and hatchetfish make a good pair. Both are fine at 75–81°F. Plan on at least 20 gal.

What temperature suits both ember tetras and hatchetfish?

75–81 °F. Ember tetras need 73–84 °F, hatchetfish need 75–81 °F.

What size tank do ember tetras and hatchetfish need together?

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