Remember that Ick appears as salt-like grains of white on the fish that is infected. It is a parasite that has a very distinct life cycle. It will drop off your fish and infest your tank substrate during parts of that cycle. Once your tank is infected, the fish that live in that tank are at risk.
There are several phenomenal threads at AA that deal with treatment of Ick. If you use the search engine to look up previous threads, you will find a wealth of information. Hypo salinity is my personal suggestion. Set up an inexpensive QT (doesn't have to be anything fancy) and treat from there. You already have an ailing fish. You don't want to take the chance of injuring other occupants of your tank. If you choose to treat with medication remember that once you expose any tank or live rock to some of those medications, it will be unsuitable for reef or coral use for some time. In general and IMO, if a treatment says it is reef safe, it is usually ineffective. The meds that are effective are not reef safe. Good luck with your fish and let us know if you have questions.
