First thing in the morning it is really pronounced and it fades all day, usually by night time it is mostly gone. Today it is really bad. Has been getting worse almost every day. Was thinking it was some sort of predator or maybe a bacterial infection. Infection would get worse daily but why would it fade away at night? My powder brown is hanging out right in the path of one outlet like he's trying to wash something off.

Try to get some pics and post them in this thread to compare.

Very strange that it would vary during the day/night, not sure what that might be, anyone heard of this? Mine has been constant, no change but seems to be fading in general now.

Myanth, I have a large dragon goby, he does not show any signs of these grey patches or any other spots.

Good news update:

The foxface has recovered as of last week there was no more grey patches. There is some discoloration almost like a scar where the grey patches used to be, but that seems to be clearing up now too.

I suspect it was a fungus or bacterial infection of some sort that the fish was able to fight off on its own.

Thanks for you help everyone.

Myanth how are your fish doing.