I got a new fish from Petsmart last night. All of the bettas were in horrible condition, with shredded fins and dirty water. A couple of them had very suspicious white dots on them, and one was DEAD, with greyish fuzzy stuff all over him. I wanted to rescue a betta from this awful situation, but I am not at all experienced with treating betta illness, fortunately, the betta that "called to me" looked pretty healthy. She is very small, so I assume young, swam around her cup nicely (not spazzing and trying to jump out like a couple were doing, but not floating lifelessly like some others). But I am still paranoid about disease, especially if equipment/materials that were used with sick fish came into contact with her or her water. I don't seen any signs of columnaris or velvet, and I don't see any white spots on her, but she is white, so I really have no idea! Maybe I'm just paranoid, but seeing those conditions makes me scared.
Right now she is in a temporary 1g container while my 2.5 g minibow gets set up (everything is in, I just want to run the new filter and new heater for a day or two to make sure everything works). Should I add aq salt to her 2.5 gallon tank for when she goes in there? What about maracyn? Or should I treat her now, while she's in the 1g? Or maybe I'm just being paranoid and shouldn't be so worried about illness since she doesn't have any signs that I can see?