I have a 5g tank with one blue crayfish and a school of minnows. They have been pretty easy to keep, feed them once a day change water once a week and that's it.
Now the cray fish is showing some withe spots on its blue shell, mainly on the front "paws". Because it is only active at night, I'm not sure if anything else is wrong with it. He still goes out from time to time for food as usual...
Is this discolouration normal? Would he be getting ready to shead its shell? Or should I be treating it for... something?