Melaflix/Pimaflix/salt
Better yet is to maintain good (over) filtration and do regular water changes and you may not ever need any meds. I keep malachite green on hand for ich but it's two years now without any need . Melaflix/Pimaflix are good for a host of minor maladies - abrasions, fungus, pop-eye fin rot, etc., but again except for the occasional combat or rough-housing injury, most of these ailments begin with/stem from poor water quality.
Just assume that like human habitats, fish tanks are filled with pathogens waiting for an opening - healthy fish with robust immune systems don't generally get sick, so if they eat well, the water is clean and they're not stressed you shouldn't expect problems.