can't tell much from the pics but if it appeared overnight then it is probably a bit of flesh or fungus that has occurred after the fish damaged itself. The fish possibly got caught under a rock and damaged the side of her body. Then it is either inflamed tissue or fungus. Fungus should appear as white and fluffy, whereas damaged tissue will be lumpy and slightly raised.
Keep an eye on her over the next few days and she should clear up if the tank is clean and healthy.
Probably oodinium and/or very virulent brooknella. These infections are somewhat common to clownfish, especially if they're wild caught. I've never heard of anyone curing a new clown which has come down with these parasites (the less virulent brookenlla can be treated though...), sorry for your loss
Certainly not contagious to shrimp . As for the fish, it is contagious. Many times with virulent cases like yours the parasite is almost too effective, killing its host before it has a chance to infect another fish. Then again, sometimes it does pass the infection on. There's no tried and true formula for this, every case is different
my female percula died a few hours after i put up the first post with the pics. my male clown i moved to my friend quaratine tank hes been in there for about a week i checked on him today his spots have dissapeared hes eating mysis and brine. i think im going to give him a few more days then ima bring my buddy back homeMy small Ocellaris has this exact thing on his face..dunjno what it is but hes acting normal and feeding ok.