Adding new fish

[Sintralcoast]

Looking to add ONE new fish to a Red Sea 250 preferably a tang. Any tips or advice on any would be appreciated or any experience good and bad. Also they will be going through a full QT.
fish I have already
Goby
Royal gramma
2 clowns
Kole tang
FISH IN MIND:
Powder blue tang
Powder Brown tang
Possible blue tang

 

[vetteguy53081]

both powder version tang- risk for ich and temperament
Consider flame angel or tomini tang