blue tang and fox face

[Mike&Pam]

I have a 90 gal reef that has been running for about 9 months now. Everything is going great. I want to add a blue tang, but am not sure it's the right thing to do. This is my favorite fish. Anyway, here's where the question comes up on whether I should: I have a foxface. He's about 2 1/2 to 3 inches long. I have about 8 other very small fish (damsel, clown, firefish, jawfish, two dwarf angels). Normally, would stop right there, but everything is has been going well for a while now and if i didn't love the blue tang so much, i would just leave it alone. The blue tang is a fish i wanted before i even had my tank but didn't do it because i knew i had to wait for the tank to mature since they are tougher fish to keep.
What does everyone think? If the answer is ok, what size should it be? Bigger or smaller than the foxface or does it matter?

Thanks everyone.

Mike