The following is an article on what believe your fish has: Brooklynella. It was a comon disease amongst wild clownfish but it is not unheard of with tank raised specimens in tanks with wild caught fish or natural wild organisms. We used straight freshwater dips to cure our fish from this ( it did take multiple baths over the course of a week however) in combination with meds with formaldehyde/formalin to prevent secondary infections ( which if they did get, were transferred into antibiotic treated water.)
Hope this helps.
What is Brooklynella? Brooklynella is a type of saltwater ich caused by an infestation of the
ciliated protozoan Brooklynella hostilis. It is most closely and commonly associated with subfamily Clownfish members of the Damselfish family, and therefore is typically referred to as Clownfish Disease. Although this parasitic scourge similar to others requires a fish host to survive, it is not particular in its quest to find one. Angelfishes, tangs or surgeonfishes, wrasses, jawfishes, and seahorses among others will host Brooklynella.
These protozoa reproduce asexually by means of simple binary fission through conjugation, which is why they are able to multiply so much more rapidly than Cryptocaryon (Marine Ich/White Spot Disease), and Oodinium (Velvet/Coral Fish Disease), and why it can kill fish within a few days and even hours upon recognition. For this reason accurate diagnosis and immediate treatment of all fish exposed to these life-threatening organisms is critical.
Symptoms to Look For
Most similar symptomatically to Oodinium, this too is a parasite that primarily attacks the gills first. At the onset fish may scrap up against objects, rapid respiration develops, and fish often gasp for air at the surface as the gills become clogged with mucus. Fish become lethargic, refuse to eat, and colors fade, but the most noticeable difference that sets Brooklynella apart from
Oodinium is the heavy amount of slime that is produced. As the disease progresses a thick whitish mucus covers the body, usually starting at the head and spreading outward, skin lesions appear, and it is not uncommon for
signs of secondary bacterial infections to arise.
Treatment Recommendation
Suggestions range from copper, malachite green and other remedies, with some recommended being used in conjunction with formaldehyde. However the general consensus is these types of medications are either largely ineffective or do not work at all, and that the best and most effective treatment for Brooklynella is formaldehyde alone. Typically a standard 37% formalin solution (
shop & compare prices) is mixed with either fresh or saltwater in a separate treatment container, intitially all fish are given a quick dip or a prolonged bath, followed by continued treatment and care in a QT. Of course the longer fish are exposed to the formalin treatment, the more effective it will be at eliminating this "disease". Whether to administer a dip or a bath to start with is something you will have to determine yourself, but there's a very simple way to do this.