Originally Posted by OMGemily
i turned the bubble thing back on (i think it adds oxygen to the water?) and he seems to be moving around a little more so maybe that was part of it... and thanks for all the suggestions :)
You shouldn't need a bubbler with bettas, in fact they prefer slower moving water and get their air from the surface like we do. In fact the bubbler might be stressing him out more.
Since you just got the guy, I wouldn't worry for now. If after a few days he still wont eat, try offering him some different foods. I have 3 females in my tank, some prefer betta pellets, others prefer tropical flakes with freeze dried bloodworm, and one even nibbles a bit at times at the bottom feeders algae wafers (though this is not something a betta should eat all the time).
Some bettas prefer some foods over others, try different types until you find what he likes.