well....to state it from the beginning I'm no expert...
I had a female who swam odd, liked to stay on the bottom all the time and then would "struggle" to the surface for air. After watching her do this for a while, I removed her, kept her in the cup from the pet store, and kept giving her salt baths, after maybe 4, 5 days she perked up, I placed her back in with the rest of the females and she's been fine...
So if you want to try salt baths here's a link for it:
http://www.bettafish.com/showthread.php?t=25297
Everything I've heard on bettafix it seems to be alright, I put it in with my girls a week ago (they all have ripped fins) and it hasn't hurt them.