Crayfish and Convict

[krazychicken703]

you just never no with fish, one min there all good next ones eating the other

 

[TwistedPenguin]

If you're not that attached to them I'd try it. There's always a reasonable chance that they'll leave each other alone. I've had things work that weren't 'supposed' to lots of times. Give the Cray little hidey holes where the fish can't get to him. Those 3-4" tall clay pots broken in 1/2 work great.
It's worth a shot-Good luck