Aquarium salt is OK, so is "sea salt" off the shelves at your grocery store, do NOT use iodized salt! Place frog in a treatment tank (bare tank, just water) and do daily salt baths. Take a spare container ("Rubbermaid" or a Kritter Keeper, with secure lid with small holes) - add one gallon of dechlorinated water around 72* and 1/2 teaspoon of salt. Let the frog remain in here for an hour. The discard the water, replace with fresh water and add the frog. Repeat the process until the bloat has cleared. If the bloat hasn't cleared up in a week, take the frog to the vet. If it is a soft bloat, most likely there would not be any kidney infection and the frog will live a long time. If the bloat becomes hard, then you need to treat with antibiotics, and unfortunately the disease can be fatal. Good luck with your frog!