I would quarantine it first thing until you do figure out what is wrong with him. That way if it is a parasite it will not infect any other fish you may have.
Thanks Jim, I think you got it right on the money. I'm a little hesitant about removing them with tweezers as the advice on the site gives. But the advice is given by Bob Fenner.
Well the parasites were removed, but so was part of the gill. The fish started rapidly declining and died shortly after. I've got some pics of the removed parasite that I'll try and post tomorrow.
Unfortunately I lost 2 peppermint shrimp in the process of getting the firefish out of the tank. Everything else seems to be doing ok.
Id love to see those pics,,, Too bad about the fish and the Pepps... Aquadome has some of the ones I collected in Port A if youre interested in replacing them.