Unlikely, but possible, especially with wild-caught. I have had hermit crabs bring in some very frightening parasites! My suggestion is put crabs in the tank while cycling, then add fish later. 'Refill' crabs - well, I've never had a problem with store bought ones, but quarantine never hurts! (Keep in mind most reef crabs are very short-lived.)

Good luck with the new tank!
Morg