Take into account that your crayfish is missing one of its big claws and is not as efficient of a hunter right now. Also, from experience danios sleep near the top of the tank away from harm's reach. If you don't mind losing a few fish here and there, maybe you could try a colony of guppies. You'll definitely end up losing some to your crayfish, but they'll breed and replenish their numbers. Also fry tend to stay near the top of the tank.