tank mates not getting along

[isaac1]

So i picked up a new addition for my tank today and for some reason my peacefull fish have turned extreamly aggressive towards there new mate witch is a powder blue tang my scopis and tomato are loseing it but theyve never had a problem before i have 1scopis 3 chromis 1 tomato 1 cleaner wrasse and my tomato has never been agressive nor my scopis untill i introduced my powder blue they are all housed in a90 gallon with 80 pounds of rock any ideas or insight on this behaviour