Seems to be a fair bit of aggression going on in the tank. The sebae is tearing into everybody and so is my powder brown tang. The powder brown is attacking all the little fish and the clown is attacking big fish, little fish...any fish. I am going to continue observing but I think that may be it. Maybe they are all stressed out with the new additions? This is what I have: Emporer (L), Naso (M), Powder Brown (M), Pr of sebae's(L&S), skunk clown (S), and a Flame angel (S). I have about 300 lb's of rock, well matured. Water quality ph 8.2, Nitrates 0, nitrite 0, ammonia 0 and phosphates test kit tested almost clear. Should I move rock around, would that help?