Question on body fungus treatment-What Meds?

This morning I noticed one of my ice blue zebras had a white cotton-like
stringy looking fuzz starting to form on him. At first I thought it was
ick, but, I did a little looking around and it appears it may be columnaris,
aka, body fungus. My pH is with in limits, water is plenty hard, temperature
is dead on, there are not too many fish in the tank....55 gallon tank, 2
zebras, 2 electric yellows, a small plecko, and 2 kenyis, all young with
plenty of rock cover. Ammonia is non-existent according to the tests I am
doing. Everything seems to be good with water quality. (I did a 10% change
yesterday as a matter of fact.)

What is the best course of action? I did add one dose of Maracyn today. I
am thinking aquarisol or copper safe, not sure which the better product is,
or even if it is necessary. HELP!!!

Also, I read the Maracyn does not require me to remove the charcoal if it is
over 5 days old. Mine is brand new, so, I just put empty bags in the
filter. Would Ammonia Chips be a bad thing to add to the filter?

What suggestions do you have?

Thanks in advance!!