Danny,
Live food will reak havock on your levels in your tank. It clouds the heck out of mine. Stop the live food for now. If he won't eat pellets, feed like 2-3 fish a day, which is still pushing it. Cut back his live food, when he get's hungry give him pellets. At first he may not eat them, but Oscars are very smart. If he sees you taking the uneaten pellets back out of the tank, next time he'll think twice before not eating them.
As far as HITH (Hole in the head), remove all carbon, weekly water changes, and lots of TLC (tender loving care).
When you change the water, use a siphon method, and suck from the bottom of the tank, and replace with fresh water of the same temp. When you pour the new water in, place a paper plate on top of the water in the tank, and dump the new water onto this. This prevents stirring up the bacteria in the gravel. Your water will stay more balanced, and clearer.
Good Luck!
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Jen
