My new crayfish won't eat and I need help?

With fish it is best to acclimate them slowly and to keep them in a quarantine tank for the first few weeks. This keeps a new fish from bringing diseases which can be fatal into a tank. It is not a good sign when a fish is not eating a stress coat can help. Watch the fish for signs of cloudy eyes and white spots if this appears the fish has ick and if not treated quickly it can kill all the fish in the tank.