I think this goldfish is sick?

Feed him less, much less. like only once a day. he is being overfed. i suggest not feeding him for a few days, or feeding him vegtables instead. Try cooked peeled peas. he might also be dying. goldfish dont live very long in bowls, and because he is eating so much the water probably has a ton of ammonia in it. Do a close to 100% water change every day. There really isnt any hope for the goldfish. Dont tap on the glass, as it adds more stress to the fish.