Hi, I have several Koi and goldfish in a mature pond. The pond is well
maintained, treated regularly with medifin and freshstart.
Also have the UV tube and filters etc.

I've had few problems over the years. Just the occasional death - probably
natural.

I currently have one goldfish which clearly has the 'swimbladder' problem.
It's been lying on it's side for about 3 weeks looking dead, but wriggles
away if I try to net it out. I don't know whether to try and put it out of
it's misery or just leave it. Could it recover ? Should I try to help it
out of it's misery ? How do I do it humanely ?

Also - just yesterday another one looks like it's swimming a bit oddly. Is
'swimbladder' disorder catching between fish or is this just a coincidence ?

What should I do ? Advice warmly welcomed.

Carole