I used to keep crayfish in bait tank's of two hundred gallon's with large goldfish,sunfish, that I use for Flathead bait untill they began killing the fish.(crayfish will also kill eat other crayfish).
Also tried them in planted tank's until they began uprooting,digging up plant's which they then munched on.
Larger african's could work but they too need larger tank to achieve proper growth ,relieve territorial disputes.(Adult fish could easily injure kill adult crayfish)
Not many fishes other than smaller barb's,danio's, (too quick to be caught,stay near the surface) that can be kept with crayfish.Larger fish,will eat the crayfish, and crayfish will eat what it can catch in the way of smaller fish.
With larger tank,,lot's of rockwork for crayfish to hide from larger predator's, one might be able to keep some of the less aggressive cichlid's with a crayfish but it seldom work's out .
The most important medication in your fish medicine cabinet is.. Clean water.