Can crayfish live with fancy goldfish?

Verdict
Yes

Yes. Crayfish and fancy goldfish make a good pair. Both are fine at 65–74°F. Plan on at least 30 gal.

CrayfishCrayfish65–77°F · pH 6.5–8 Fancy goldfishFancy goldfish65–74°F · pH 7–8

Why it works

Water side by side

55°60°65°70°75°80°85°90°Both: 65–74°Crayfish 65–77°Fancy goldfish 65–74°
The green band is the temperature range both can live in.
456789Both: 7–8Crayfish 6.5–8Fancy goldfish 7–8
The green band is the pH both tolerate.

Size to scale

Crayfish · 5 inFancy goldfish · 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

CrayfishFancy goldfish
Temperature65–77 °F65–74 °F
pH6.5–87–8
Adult size5.0 in6.0 in
Minimum tank20 gal30 gal
TemperamentAggressivePeaceful
Swims atBottomAll levels
GroupOne per tankAlone or in pairs
DietOmnivoreOmnivore

Better tank mates for crayfish

All crayfish tank mates

Better tank mates for fancy goldfish

All fancy goldfish tank mates

Questions

Can crayfish live with fancy goldfish?

Yes. Crayfish and fancy goldfish make a good pair. Both are fine at 65–74°F. Plan on at least 30 gal.

What temperature suits both crayfish and fancy goldfish?

65–74 °F. Crayfish need 65–77 °F, fancy goldfish need 65–74 °F.

What size tank do crayfish and fancy goldfish need together?

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