<a href=showthread.php?s=&postid=12843290#post12843290 target=_blank>Originally posted</a> by stagefright13
Yep you are right. You can't kill everything with fresh water! Even a drop of the water may contain hundreds of parasites.
The slime coat on a fish resists water. As Slakker said it defeats a fresh water dip. At least at levels that the fish will survive. And how do you not transfer water with the fish????
Even the most casual observer will notice that a new fish will benefit more from good water. And less stress. Stress and weakness allows ich and other diseases to take over.