Rash guards are good. The best way not to get ring worm is to have healthy, intact, clean skin. If you have dry skin then it's weak skin. Cuts, scrapes, pimples. All that leads to openings for stuff to get in. Above all never scratch. Finger nails are the dirtiest thing going. Scratching just breaks the skin and drives the crap into it. Good skin care will prevent more nasty stuff then a rash guard.