Question
Hello,
My 8" comet has been struggling for 6 months now. It began with it having difficulty swimming below the surface and it was usually floating upside down. It has gotten worse this week and it's belly looks like a large white bubble. It can no longer swim under the water at all. I have never known a fish to hang on this long, under such difficult conditions! I wish I could help it and your advise would be greatly appreciated.
Thank You, Lilli

Answer
I'm sorry about your fish.  Normally it's fancy goldfish that have problems with buoyancy.  They can get swim bladder disorder.  The belly is a bubble?  Is the fish just really large or is there an actual bubble?  Is the comet in a pond?  Does it look like some of the fish on this page on my site (mostly the first fish I had)?
http://www.fishpondinfo.com/health5.htm
If the fish has an internal bacterial infection, it is very hard to treat.  See http://www.fishpondinfo.com/gfish4.htm and http://www.fishpondinfo.com/fishcare/treat.htm for a few ideas.  I hope things improve!

Robyn