Welcome to the board! 8)
Well, before i make any coral reccomendations, i'd like to address a few things. Is the tank really only 4 weeks old? (the name of the pic is week4, and it looks brand new) If so, i'm assuming that your tank has cycled, since you already have a bubble tipped anemone. Unfortunately, the purple tang, although somewhat small now, is going to need much more room than your 29 has. I'd reccomend returning it to your LFS in favor of a fish more appropriate for your size of a tank (cardinalfish, various gobies, etc...).
Assuming that your water chemistry is in good shape (pH high and stable, undetectible ammonia and nitrite, strong Ca and dKH), hardy corals for your lighting would be mushrooms, leather corals, polyps, and star polyps for starters. Just take it slow, but an anemone is not a good item to throw in the tank first (although i'm glad it is a BTA). It should be fine though, provided your tank is fully cycled and you take it slow from here on out.
