2-3 weeks ago I put good fish in my tank to see how the water is in my 125 just set it up about a month ago. They did great so I got a silver aro a Florida gar and a CK but the past few days all the gold fish got cloudy eyes and a white film on parts of there body and also looks like some fin rot too. NOW MY CL LOOKS LIKE THAT!!! please help don't know what it could be. All goldfish died. Don't want the CK dead. Did water change added some salt plus my other chemicals. Amy help would be greatly appreciated. Thank you all