It was about a year ago that I had 2 tiger oscars, about 4" each in my 100g. Anyway, I came downstairs late one night and saw a black spot on the floor by the tank with the lid up. Upon further inspection, I found one of my oscars dryed up and motionless. Wasn't even gasping for breath. I tossed him into my q-tank and he floated belly up. But I had this strange feeling inside me, so I left him in overnight. The next morning I found him swimming again! A little slowly but he was alive.
Also, every time I put my hand over the tank to feed them, they jump completely out of the water trying to snatch the food out of my hand.
I don't know if all oscars have a reputation for jumping, but if anybody tries to tell me they don't, I'd have to refute.