Honestly, Oscars are prone to sulking. It's what you're seeing now.

I have one as well, and he did that. If he's small...he should snap out of it fairly quickly.
I just moved mine, and myself, from an upstairs apartment to a down stairs. My Oscar has sulking for a week. I swear, at one point, I thought he was dead. But, they are tough fish, and just don't handle changes well...they get whiny and crybaby-like. Of course...watching them will tear your heart out.

He'll be fine, I'm sure. Just do regular maintainence, make sure he gets some attention...Yeah, I pet my Oscar. LOL And he should be fine in a few days.
