Betta fish SB/Finrot?

I can't really tell anything wrong with the fish from these photos.
Do you see anything out of ordinary in the fish's behavior?

Do not use medications on the first sign of what might seem to be problems. Many medications are hard on the fish and can bring more harm than good in some cases. I have had fish died to medications rather than the problems the medications were designed to counter. At this point, the best you can do is to provide excellent water quality and do not overfeed your betta. Minor problems will just go away by themselves.