Can crayfish live with jack dempseys?

Verdict
Yes

Yes, crayfish and jack dempseys can live together. Both are fine at 72–77°F. Plan on at least 55 gal.

CrayfishCrayfish65–77°F · pH 6.5–8 Jack DempseyJack Dempsey72–86°F · pH 6.5–7.5

Why it works

Water side by side

55°60°65°70°75°80°85°90°Both: 72–77°Crayfish 65–77°Jack Dempsey 72–86°
The green band is the temperature range both can live in.
456789Both: 6.5–7.5Crayfish 6.5–8Jack Dempsey 6.5–7.5
The green band is the pH both tolerate.

Size to scale

Crayfish · 5 inJack Dempsey · 10 in0"2"4"6"8"10"
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

CrayfishJack Dempsey
Temperature65–77 °F72–86 °F
pH6.5–86.5–7.5
Adult size5.0 in10.0 in
Minimum tank20 gal55 gal
TemperamentAggressiveAggressive
Swims atBottomMiddle
GroupOne per tankAlone or in pairs
DietOmnivoreCarnivore

Better tank mates for crayfish

All crayfish tank mates

Questions

Can crayfish live with jack dempseys?

Yes, crayfish and jack dempseys can live together. Both are fine at 72–77°F. Plan on at least 55 gal.

What temperature suits both crayfish and jack dempseys?

72–77 °F. Crayfish need 65–77 °F, jack dempseys need 72–86 °F.

What size tank do crayfish and jack dempseys need together?

At least 55 gal, set by the jack dempsey. Add space for each extra fish.