FW dip offers temporary relief and nothing else. Not sure why many are recommending it as it imposes a level of stress on the fish.
What you are seeing are kidney-bean shaped microscopic parasites covered in cilia which is a product of brooklynella. Thereafter, the fish will become lethargic, refuse to eat, and its colors will fade. The most noticeable difference that sets Brooklynella apart from Oodinium is the heavy amount of slime that is produced by a fish that has contracted this parasite. As the disease progresses, a thick whitish mucus covers the body. This will usually start at the head and spread outward across the entire body. Skin lesions appear and it is not uncommon for signs of secondary bacterial infections to arise, such as redness and fin rot.
I believe Jay made mention and you will need to treat with Formalin which has been found to be an effective treatment for Brooklynella as well as other parasitic diseases. My preference is either API General Cure or Ruby Rally reef with General cure more effective. Typically a standard formalin solution is mixed with either fresh or saltwater in a separate treatment container. Initially, all fish are given a quick dip in the formalin at a higher concentration, followed by continued treatment in a prolonged bath of formalin at a lower concentration in a quarantine tank (QT). Of course, the longer the fish are exposed to the formalin treatment, the more effective it will be at eliminating this disease.