which tang would you buy?

its not a tang but koran angels are really cool and its funny watching them mature and change colors

 

IMO the Blonde Naso is the most beautiful Tang along with the Powder Blue.

 

El, as I told you in your build thread you need to QT your fish. Read up on it and never introduce them into your dt until there properly qt. Powder blues can be difficult but the browns are a little hardier. Most tangs are more ich prone than other fish. I'd get a nice yellow or a purple but make sure you qt and offer plenty of algea sheets since your tank is so young.
I wouldn't be afraid to get a naso in your 150. They do get big but you don't see 12" naso everyday so you've got some years before you'll have an issue.

Matt:

 

Lieutenant Tang

 

I am fond of the hippo tangs. But they will outgrow a tank that size eventually. I have one in a 90g....but it is of a size that is acceptable at the moment. Once they get big though, they require much more swimming room and they can deplete oxygen in a tank. Active fish they are.

 

A real good suggestion and there reasonable priced and not everybody has them.

Matt;D