.... errr, and treat with WHAT? U didn't say what to treat with if it's gill flukes.

I'm not too sure if it's gill flukes or not. If it's flukes your fish will have tell tale signs like flashing. It would be rubbing it's gill cover/body on hard surfaces to try remove the irritant. Now if it's already listless and floating, and it's caused by gill flukes, u've let it go on for too long. U should catch it early. Basically, the only sure way to dignose gill flukes is with a microscope.

Treatment for flukes: Dimilin, Trichlorofon (usually this is the active ingredient in Fluke Tablets such as ParaEX by Wardley), or Praziquantel (active ingredient in Droncit).

Check out www.goldfishconnection.com for infomation on medication. It's an American commercial site but it's got good info and Rick Hess (owner of Goldfish Connection) is among the biggest buyers of top quality goldfish from around the world.