[naesco]

If it looks fuzzy as opposed to spots, pimples or salt like specks it is probably a fungus.
An excellent product is made by Mardel but you have to remove the fish into a QT to do it.
It will clear it up quickly
Rocks do not get fungus so forget about the rocks.
A freshwater dip will do nothing for fungus except stress the fish.
Continue with the garlic extract but add a few drops of selcon because when the fungus is killed the sore needs to heal.

Check your water parameters because fungus often surfaces when water quality is not up to par although it might have come in with the last fish you added.