I have had a yellow tang in my main tank for about 2 months now. I'm noticing now that if I go near the tank he seems to become agressive and display alot. When i say display it's like he leans back (looking at me from the side) and flutters his front fins. I've taken my camcorder and let it run while I am not in the room and he is as peaceful as can be. Any ideas as if this is normal or something to do (besides the obvious, don't go near the tank)? Thanks.