I guess I'm not 100% sure if my betta is sick or not. She's the first fish I've had.
She has a small white splotch on her stomach that I hadn't noticed before, right in between the thin red ventrals. She's been in her aquarium for about two days, with no noticeable behavior changes. But, like I said, I don't really know how she normally acts yet. She stays in one corner of the aquarium a lot, near the surface. Generally switches between chillin' out and swimming around crazy at a pace I imagine is normal-ish.
EDIT: There is this kind of clear scum floating around at the top of the water. I don't know if that is relavent.