goldfish behavior

Question
My goldfish just sits at the bottom of the tank, lopsided. If another fish pesters him he'll swim around but then go back to the bottom of the tank.  What's wrong with him?

Answer
I would examine his body to make sure it is first not a disease or parasite. Does he have any odd symptoms on his body, such as salt-like spots, bumps, fuzzy films, torn rotted -like fins, cloudy or red eyes, and so on? If not, I would assume the behavior is because of the pestering fish. While goldfish tend to be peaceful fish, they sometimes can be bullies in search of the alpha rank. Also, one other possibility is, how big is the tank and how many inhabitants and does it have an air stone? Maybe he is low on oxygen? Goldfish require a large amount more of oxygen than other fish and usually require an air stone to be happy and healthy and active. Let me know the answers to my questions and I will continue to help you figure out this issue.