I was thinking maybe he's bored/lonley. I have 4 about that size in a 300g. seems like they enjoy interacting at times. Other times they ignore each other. Maybe you should find him a mate?
I've been thinking about finding it a buddy, but if I do get another Oscar, it's going to have to wait until the arowana moves out next month. There's not enough room in the 90 to divide up the tank and grow out another Oscar at the moment.
Here's a little update. I got home today and my Oscar is back to its normal color and is swimming around. Yay! It still is afraid of me and refuses to eat, but at least its not turning ghost white and sitting at the bottom. Hopefully he'll be completely back normal within the next few days. Seems like I'm going to have to go buy some black posterboard. Thanks for everyones replies.