white spot on puffers eye?

[iservicebox]

my girlfriend has a valentini puffer that has come down with a white spot on his left eye. She has had him for about 6 months and the other day she said it was lying on the sand moving very slowly. Then the next morning it was fine. Im concerne about the white spot, it's bigger than what ICH looks like. what could it be? also she has copper in the tank, but dont worry its just fish and base rock.

 

[HoopsGuru]

Not sure about the white spot without a picture, but copper is toxic for puffers. Copper should only be used on fish with scales, puffers of which have none. I would remove the puffer to a hospital/quarantine tank or get a polyfilter and remove the copper (as much as you can) immediately.

What are you treating the tank with copper for? (I assume other fish are "ill"?)