Originally posted by Kater
The symptoms you are describing sounds like it could be....

-fin rot
-swim bladder disorder - due to overfeeding
-internal parasites
-unknown-possible depression

No matter what it is, a full water change in is order!!!
If that is what her Betta has they have antibiotics made just for that. It's really the best way to go to heal the Betta. They don't cost that much if your worried about her fixed income.