Can crayfish live with ember tetras?

Verdict
Yes

Yes. Crayfish and ember tetras get along in the same tank. Both are fine at 73–77°F. Plan on at least 20 gal.

CrayfishCrayfish65–77°F · pH 6.5–8 Ember tetraEmber tetra73–84°F · pH 5.5–7

Why it works

Water side by side

55°60°65°70°75°80°85°90°Both: 73–77°Crayfish 65–77°Ember tetra 73–84°
The green band is the temperature range both can live in.
456789Both: 6.5–7Crayfish 6.5–8Ember tetra 5.5–7
The green band is the pH both tolerate.

Size to scale

Crayfish · 5 inEmber tetra · 0.8 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

CrayfishEmber tetra
Temperature65–77 °F73–84 °F
pH6.5–85.5–7
Adult size5.0 in0.8 in
Minimum tank20 gal5 gal
TemperamentAggressivePeaceful
Swims atBottomMiddle
GroupOne per tankGroups of 6+
DietOmnivoreOmnivore

Better tank mates for crayfish

All crayfish tank mates

Better tank mates for ember tetras

All ember tetra tank mates

Questions

Can crayfish live with ember tetras?

Yes. Crayfish and ember tetras get along in the same tank. Both are fine at 73–77°F. Plan on at least 20 gal.

What temperature suits both crayfish and ember tetras?

73–77 °F. Crayfish need 65–77 °F, ember tetras need 73–84 °F.

What size tank do crayfish and ember tetras need together?

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