Black Moor with persistent swim bladder

Question
Our black moor is nearing 5 years old.  She lives in a 66 gallon tank with 3 other smaller goldfish.  Water quality is great - we are somewhat experienced goldfish owners.  This black moor has had this issue 2 or 3 times before and bounced back, but this time she is not recovering.  We have tried some epsom salt and placed her alone in a separate smaller tank. We feed a little bread, sometimes a chopped pea - nothing seems to work.  She lies upside down on the bottom of the tank most of the time, but does swim around once in a while.  While she is very strong we know this cannot last too long.  Are there any more direct or drastic measures we can try?  thanks so much for any help you can provide.

Answer
Marcel,
Fast her for 2 days. On the third day feed her the cooked shelled pea, then fast her again for 2 days. DO NOT feed her bread. It is not good for fish. This is the way that I treat swim bladder. Try not to over feed them. Here is a website that covers why they get it and things you can do to help prevent and treat this problem. I hope it helps you out.

http://thegab.org/Illness-and-Treatment/buoyancy.html