I have had mine in my reef for nearly 3 years and no problems. I used to have a hogfish that bothered the hawk but I took the hog out.
My Hawk does not bother my inverts or corals or other fish but other ppl. have said that they can so it all depends on that one fish and you system. I have plenty of LR and a fuge so my hawk is well fed. I love my hawk, very cool fish. Mine will sit in my hand and eat food from it.