ok, so in my 120g i have a yellow tang thats about 3 inches and i just got a small sailfin thats just about an inch long. i have a blue hippo that is an inch and a half and him and the sailfin do great, but the yellow flares its fins and looks like it might be starting to get closer to being aggressive with its barbs towards the sailfin. will these 2 calm down or, because he doesn't mess with the hippo, just the sailfin. I think its because their both yellow... but he has driven the sailfin to the dark corner behind my rock and he won't come out. What should i do?