To my understanding EG are reef safe. Ive had my EG for about a year now, I got it when he was the size of a quarter and now he is almost 10 inches long. Never in his life has he bothered any of my 8 chromis or any other fish. What im thinking however is that your chromis are simply dying and he is just eating the bodies not actually killing them. Chromis are known to die for no reason pretty quickly on a tank. ( at least many people say they die within a few weeks of having them on the tank) Ive had 8 chromis for about a year and they are doing well **knock on wood* either that or you have something else in the tank. I really doubt your EG is killing them. i just cheked the date of this thread.. 2 years old..