If they will eat add Metroplex (medication) and Focus (binds medication too food) to mysis shrimp. Add ONLY a tiny bit of metroplex it is a very powerful drug. If the ick is really bad you might have to do freshwater dips. If you have never done a freshwater dip I highly suggest looking up a form on here or calling your lfs
. There is some risk involved preforming a freshwater dip. Saltwater parasites can't survive in freshwater and visa verse.