I recently purchased a school of 3 Mono Sebae in pure freshwater. I add salt to my tank with every water change. The second day I had them white spots began to appear along their sides. They are raised up like cysts. And have not spread to their fins. I've treated with water changes, and I'm almost done with a 7 day treatment of melafix. I still have seen no real loss of the spots. The fish are active and eating well though, and none of my other fish have contracted any spots. What treatment should I pursue next? I have them with a Male motoro stingray, so I'm iffy on what medicine is safe, besides nothing with heavy metals