what is this?

My husband bought me a new lionhead last weekend and he is currently in
quarantine. A couple of days ago he started developing little white spots (2
or 3 mms wide and about 2 mm high in little round blobs) on his head which I
thought at first was new headgrowth. The next day though he had about 10 of
these spots so I took him out to have a look and they scraped off easily
with my finger nail and were slimy and sort of like pus. Left on the fish
though were tiny red marks. One has appeared today on his body and after
swabbing the white stuff off there is a bloody scale underneath. First
instinct is a parasitic infection of some kind, but I have been reading
about flexibacter/columnaris and read on one site that you can get a little
red mark with fungus growing on it. As I've never had a case of fungus
before, what is it like when a fish is removed from the water? Does it stay
fungussy/woolly, or is it like slimy pus?
I have a med here which treats protozoan parasites as well as skin and gill
flukes, and I have one which treats colomnaris/flexibacter.
Which should I use?