The other day I was at Petco and found a sickly looking Betta. His cup said "Adoption $2". I had a cycled 10g at home so I took him home! Store said he was brought in when a landlord found him left behind by a tenant. He has some fin rot and at first was just kind of floating around, he has become very active and gained some size. Do I need to medicate the fin rot? Or can I just do water changes and he should pull out of it? Sorry for the poor pic, I'll post a better one soon.