I agree with the idea of quarentining the Powder Blue and of course should be done for any new fish. Powder Blue's are like many tangs and worse than most in that they are ick magnets. However, once they are established they eat quite a bit and need plenty of food (especially greens). They also tend to be quite aggressive so be warned. The tankmates you mentioned should be alright except maybe the Yellow Tang. The Princess Parrotfish are cool but parrotfish tend to be hard to feed from what I have heard. Don't have too much experience with them though. I do know in the wild they consume a lot of algae and crush coral and rock into sand.
James
James
