BTW: what your fish have is most likely an Uronema marinum infection on bite wounds. It is an opportunistic ciliate, normally living of bacteria and dead fish and often present in fish tanks, living of the bacteria on detritus and leftover food without doing harm. But if water conditions get bad - low pH, high ammonia and too cold, conditions like you have often during shipment, it can infect the fish's gills and skin. An infection becomes even more likely if the fish has also fresh wounds from fighting or handling.
Formalin & malachite green is the right medication for the treatment tank but you may also want to get some Methylene blue for additional dips if it doesn't get better. You also may need to treat secondary bacterial infections with antibiotics.
As for feeding him I would try some live brine shrimp nauplii. Not the most nutritious food but usually something even picky or sick fish go after.
Thank you so much for the post!!! I hav some meth. Blue on hand so i'm ready. I will start a culture of BBS tomorrow and see if he's bite. Thanks again to everyone for the help!!


