there are some who have had success with them, but arrows definitley can and often do(but not always) eat shrimp, worms, crabs, and smaller fishes, jsut about anythint they can get their claws on, they will, they are so cool, you just have to use caution wth them, b/c they sometimes do and sometimes don't pose a problem
simply put, they can and often do, so just watch him