Can crayfish live with swordtails?

Verdict
Yes

Yes. Crayfish and swordtails get along in the same tank. Both are fine at 72–77°F. Plan on at least 30 gal.

CrayfishCrayfish65–77°F · pH 6.5–8 SwordtailSwordtail72–79°F · pH 7–8.3

Why it works

Water side by side

55°60°65°70°75°80°85°90°Both: 72–77°Crayfish 65–77°Swordtail 72–79°
The green band is the temperature range both can live in.
456789Both: 7–8Crayfish 6.5–8Swordtail 7–8.3
The green band is the pH both tolerate.

Size to scale

Crayfish · 5 inSwordtail · 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

CrayfishSwordtail
Temperature65–77 °F72–79 °F
pH6.5–87–8.3
Adult size5.0 in5.0 in
Minimum tank20 gal30 gal
TemperamentAggressiveSemi-aggressive
Swims atBottomMiddle
GroupOne per tankGroups of 3+
DietOmnivoreOmnivore

Better tank mates for crayfish

All crayfish tank mates

Better tank mates for swordtails

All swordtail tank mates

Questions

Can crayfish live with swordtails?

Yes. Crayfish and swordtails get along in the same tank. Both are fine at 72–77°F. Plan on at least 30 gal.

What temperature suits both crayfish and swordtails?

72–77 °F. Crayfish need 65–77 °F, swordtails need 72–79 °F.

What size tank do crayfish and swordtails need together?

At least 30 gal, set by the swordtail. Add space for each extra fish.