I cleaned my tank and filled with fresh water. About 2 hours ago he looked as if it was shedding it's skin. Now about 2 or 3 hours later, all the skin-shedding is gone and my fish looks as though he has brand new smooth skin on him. I hope I haven't shocked him when I was putting the water in the tank as I was pumping the old water out. I've never seen a fish shed (like a snakes sheds skin). What have I done wrong? He is not floating sideways or anything. He is just going from one end of the tank to the other one and he is just tagging along side my algae eater. Please advise.

sounds strange. never heard about this problem. you mean that all of his "skin" is replaced?

it's much easier if you post a pic of him..........

I have been on google for the past 2 hours trying to find anything about Oscars shedding but can't find anything. I'm very interested in what the Mods have to say about this.

oscars have scales and scales are different from the skin where
they are attach. shedding skin means your oscar is scaleless by now.
is that what you mean?????? shedding scale is posible but not all
scales, otherwise your fish is in trouble.

what i believe is that your oscar develop slimy covering when you
do water change.... may be due due some salt or chemicals present
in your water.... and eventually shed it off, but not the skin.

however.... a picture can help us evaluate. plus the water parameters....