Interestingly enough.. I have an Apisto. eunotus female, subdominant, that has these areas on her tail that are white/grey and also seem fuzzy. However, the area is NOT visibly raised from any angle and the spot is NOT round in any way and the borders of the area are not well defined (I thought that was more concise than "fuzzy"). Tank conditions are pristine and everyone's been around for ages now. After much observation I realized that the dominant female of the colony is trying to spawn with the dominant male and she is attacking/biting the tail of my subdominant female in order to get her out of her territory! The spots I'm seeing are actually bite wounds, if you could call them that, and are areas where my female is slowly repairing her fins.
It is entirely possible that your fish have ich, but spend some time observing them for aggression (and flashing, as another suggested). If you see them biting one another near their fins it's possible your case is like mine. Just a thought.
