White spot on clown

[Shannon Harlan]

I was working on my tank today and saw a spot on top of my clown. Any suggestions as to what it is. Our skimmer went out last week and just installed a new one just an hour prior to noticing. It is on the very top off him right between his two big real white spots. Also I glued a zoa patch to a rock, could it have rubbed against glue that didn't dry? It's very thin looking.

 

[ndz98]

Maybe he got stung by one of the corals in your tank. Is it still there?