My oscar is spitting up white flakes?

Our tank seems to have been bombarded witha virity of ailments. Our oscar seems to be the only one negitvly effected by these. He start getting white crstal like things on his fins so we treated it for ick, the water started getting extremely cloudy so we did a 25% water change and treating with stress coat. Then we started seeing little wormy things floating around so we started feeding the fish less. Oscar spit up a few of these worms. Now Oscar has just been fed about 5 minutes ago and he is spitting up white flakes. Could this just be the food broken down now that he's spitting up or is it something else?