Hole-in-the-Head disease is most often associated with cichlids, although it does occur in some other fishes. Small holes appear, usually in the region of the head, although they can occur near the lateral line. These gradually enlarge and increase, eventually emitting a yellowish mucus that trails through the water. It's caused by the protozoan Hexamita.
As far as the use of "feeder fish" causing this problem, I don't think so. I've used feeder fish for all my fish large enough to eat them for over 40 yrs, and only had to deal with HitH twice.
I believe that just as healthy humans are normally able to resist viral, and bacterial infections, so can healthy fishes. Should they become weakened in some way, however, perhaps through transportation, overcrowding, or poor aquarium conditions, they will sicken and, if a suitable treatment, or a change in conditions are not applied fairly quickly, may die.
There are OTC medications available in neghborhood pet shops;
"Clout" by Aquarium Products
Hole-in-the-Head Guard by Jungle
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