I kept an amazing little C. argi for a couple years, absolutely loved that fish. He definitely had the "Napolean complex" as Todd put it, but was in a 150 gal so basically just chased fish here and there, never did any real damage (to fish). This tank was a "mixed reef" with wellsos, acros, montis, xenia, etc., and he didn't touch anything... for at least a year and a half. This was my first experience with "...and one day the angel might change it's mind." I came home and all three of my wellsos had been torn into, flesh ripped off of half it's body just swaying in the flow. I moved them into a different system and let the fish stay.