i use amquel plus and have necer lost a fish and my city water is bad,tried prime once didnt see any difference,plus around here amquel plus is cheaper by thee gallon and does the same job,its all just personal experience and preferrence,i am not a scientist so i do not have a lab to test actually which one works better,if the one you are using works for you than use that one,dont play follow the leader cause everyone else does,if stress coat works for youthen use that,if prime works than use that,i think everyone has lost a fish for some reason or other and just blame it on something to ease there minds,fish can be lost from temprature shock,ph shock etc,not just always conditioner.