Why is your goldfish bleeding?

Probably because its water is putrid. My advice is to do a water change ASAP. Then follow the basic rules for keeping fish. The fundamental rules for keeping any kind of fish are :- 1 inch of fish needs a minimum of 1 gallon of water. (more is much better) :- Every tank needs a permanently running cycled filter (it neutralises ammonia) :- Every tank needs at least 50% of its water to be replaced every week. (Keeps excess nitrate levels low) If you keep to the above rules your fish may stand a chance of survival. If you don't keep them I can guarantee that you will constantly have problems with your fishes health.