I am personally not a fan of this shrimp. Those claws aint for nothing and if it can catch a fish, well, you get the idea.
If its "nipping" at fish this can cause stress which can lead to the immune system weakening making it easier for the dreaded ich to rear its ugly head. Have also seen these guys go after cleaner shrimp, peppermints, snails, all sorts.
IMO, not the safest shrimp to put into your tank. They are cool when they are little but more often then not turn into a headache.