Alive floating Gold fish

Question
About 4 years ago i bought 2 goldfish and they lived in a tank for about 3 years, but last summer i put them both in my new pond. During there time in the tank i noticed that one of them started getting a little fat, but thought nothing of it. Since its been in my new pond, its became alot fatter and it started to some times float upsidedown. But now it is nearly constantly floating upside down and is struggling to feed as it cannot stay upright and is extreamly fat. Is there anything i can do to help my poor goldfish?
Thanks in advance.

Answer
Hi Sean,
thanx for your quesiton.  Your fish could have a number of problems.  It could be a tumor, swelling from a viral or bacterial disease, swim bladder problem, constipation.  Here is a URL which has some information you may find useful.  In my opinion, if the fish doesn't get better in a few days, you should put it down.  I hope this helps.
Tom

http://www.fishdoc.co.uk/FAQ.htm#swollen