Can crayfish live with silver dollars?

Verdict
Yes

Yes. Crayfish and silver dollars get along in the same tank. Both are fine at 75–77°F. Plan on at least 75 gal.

CrayfishCrayfish65–77°F · pH 6.5–8 Silver dollarSilver dollar75–82°F · pH 5–7

Why it works

Water side by side

55°60°65°70°75°80°85°90°Both: 75–77°Crayfish 65–77°Silver dollar 75–82°
The green band is the temperature range both can live in.
456789Both: 6.5–7Crayfish 6.5–8Silver dollar 5–7
The green band is the pH both tolerate.

Size to scale

Crayfish · 5 inSilver dollar · 6 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

CrayfishSilver dollar
Temperature65–77 °F75–82 °F
pH6.5–85–7
Adult size5.0 in6.0 in
Minimum tank20 gal75 gal
TemperamentAggressivePeaceful
Swims atBottomMiddle
GroupOne per tankGroups of 5+
DietOmnivoreHerbivore

Better tank mates for crayfish

All crayfish tank mates

Better tank mates for silver dollars

All silver dollar tank mates

Questions

Can crayfish live with silver dollars?

Yes. Crayfish and silver dollars get along in the same tank. Both are fine at 75–77°F. Plan on at least 75 gal.

What temperature suits both crayfish and silver dollars?

75–77 °F. Crayfish need 65–77 °F, silver dollars need 75–82 °F.

What size tank do crayfish and silver dollars need together?

At least 75 gal, set by the silver dollar. Add space for each extra fish.