I've never before used salt with any of my rays, but for the first time one of mine has some redness at the base of it's barb (where the sheath goes around it) from when I moved them yesterday. I think he'll be just fine, but I'm thinking of using salt this once as a preventative for a fungal or bacterial infection, just to stay ahead of the game. I'm going to give him the rest of today just to see what happens, and I don't want to salt the tank after he's back to normal again. It just makes me nervous to try something new with my rays - I'd hate for anything bad to happen!