I don't want to sound like a mean, self-righteous bastard but if there's one advice I could give you - that is research what you intend to keep.
If I remember correctly, 15 gallons yung tank mo hindi ba?
Here's the tank requirement of common tangs
http://reefcentral.com/forums/showthread.php?t=1946079Trust me, there are good reasons why you should not keep a tang (even a juvenile one) in a very small tank, even if the tank is just FO or FOWLR.
If you plan to stick to this hobby, at least start on the right track. It will save you from lots of unnecessary fish kills, expenses and heartache... or headache. Or both.
Take wisdom from our tips, so you won't do the same mistakes we did. Konting effort lang ang research pero sobrang laki ng return.