Why won't my goldfish eat?

I just got a goldfish yesterday. I won him at the carnival. I have been keeping him in a big tupperware bowl for now but I will get him a tank as soon as I can. I know they like to get comfortable in a corner or nook so I put a few pool toys in there where he can settle in. Remember, THIS IS JUST TEMPORARY! Now I know the "carny fish" don't last very long because of diseases and stress, but I really want to keep him for a while. Maybe about a few months or longer would be nice. I wasn't able to get him fish food last night because I left the carnival at 11 pm and nothing was open then. I decided to feed him a flake of cereal last night and he wouldn't eat it. I figured he would be fine until morning when I could get him some fish food. My mom is going to take me to get fish food soon but I really wanted him to eat earlier. I gave him a pinch of bread crumbs today and it seems like he is eating it but I don't think he is. He swims past it and after that there is no bread crumbs where he had just swam. It looks like he is sucking them in but then I see them float off to the side. in a pile. I'm not sure if he is eating or not. I just checked on him and it seems that he has eaten most of the bread crumbs because there are a lot gone. I am just not sure if he is eating. Please help!