Can crayfish live with serpae tetras?

Verdict
Yes

Yes. Crayfish and serpae tetras make a good pair. Both are fine at 72–77°F. Plan on at least 20 gal.

CrayfishCrayfish65–77°F · pH 6.5–8 Serpae tetraSerpae tetra72–79°F · pH 6–7.5

Why it works

Water side by side

55°60°65°70°75°80°85°90°Both: 72–77°Crayfish 65–77°Serpae tetra 72–79°
The green band is the temperature range both can live in.
456789Both: 6.5–7.5Crayfish 6.5–8Serpae tetra 6–7.5
The green band is the pH both tolerate.

Size to scale

Crayfish · 5 inSerpae tetra · 1.75 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

CrayfishSerpae tetra
Temperature65–77 °F72–79 °F
pH6.5–86–7.5
Adult size5.0 in1.75 in
Minimum tank20 gal20 gal
TemperamentAggressiveSemi-aggressive
Swims atBottomMiddle
GroupOne per tankGroups of 6+
DietOmnivoreOmnivore

Better tank mates for crayfish

All crayfish tank mates

Better tank mates for serpae tetras

All serpae tetra tank mates

Questions

Can crayfish live with serpae tetras?

Yes. Crayfish and serpae tetras make a good pair. Both are fine at 72–77°F. Plan on at least 20 gal.

What temperature suits both crayfish and serpae tetras?

72–77 °F. Crayfish need 65–77 °F, serpae tetras need 72–79 °F.

What size tank do crayfish and serpae tetras need together?

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