Actually salt does the same thing and more than stress coat does. But what you need to do is get a test kit for ammonia and nitrite and nitrate. and find out what your reading are. There could be a undelying reason why this happened to your fish. When a fish is healthy and placed in a healthy enviroment the do fine most of the time. But when a fish is stressed from several factors like a move or unhealthy water conditions that is when they will be attacked by these bacteria infections.