Sorry to say, but a FW dip will do more harm than good. Do you have a FO, FOWLR, or a reef? If you have a FO then you could do hypo or copper in the main tank(think about the copper part REALLY good before you add it to the main.) If ya got a FOWLR or a reef, your gonna have to move ALL of your fish to a separate hospital tank for treatment, and then do the hypo or copper. Hyposalinity and copper are the BEST methods for CURING ick, don't let anyone tell you different. Also, if ya got a reef tank, you'll need to let the main tank go fishless for a min of 30 days to let the ick die off due to no host. I've have been in your shoes before, and I did all of the "stupid stuff" before I knew of this board. FW dips are effective in some diseases, but for ick.... NO WAY!! If you do a FW dip on your fish, they will look a little better for a day or two. Then the ick not only comes back, but in most cases it will come back worse. HTH
