Do you have a QT set up? If you do, i would suggest moving the fish it and using either Copper or Hyposalinity to treat them.
Copper:
Romove all of the fish from your main tank and add them to the QT. Make sure you do not have any
LR,
LS or inverts in the tank, because copper will kill them, and it is impossible to remove copper from rock once it is introduced. You should have something in there for the fish to hide behind, like a fake plant or fake rock. Make sure that you have a
Cu Test Kit, and test the water often. Remove carbon from your filter, it will remove the copper from your tank. Add the copper to the tank slowly over serveral days to .5ppm. I would suggest Cupramine. Keep the
Cu level at .5ppm for 4-6 weeks, and feed garlic infused foods, sparingly. Keep no fish in the main tank for 4-6 weeks, this will kill the parasite's life cycle because they have no fish to leech on to.
Hyposalinity:
Place all of your fish, no inverts, into your QT and slowly lower the salinity to 1.009.
See this link for more info
http://www.petsforum.com/personal/trevor-jones/hyposalinity.html
If you dont have a QT, see my thread on No-Ich
http://www.aquariumadvice.com/viewtopic.php?t=4720&highlight=
I hope this helps. Good luck