Parapercis schauinslandii ... usually called red-spotted sandperch. So not a real blenny or perch or whatever. Sandperches are also called grubfishes, and I have seen the sandhopper blenny name as well (though it's a bit confusing). Most species eat smaller fishes and crustaceans, but some eat plankton. I can't image they would cause too many problems in a reef tank ... aside from eating all the smaller fish and crustaceans.
Tony