Sick Goldfish advice

[tarmac]

Hi Folks. One of my original Goldfish developed a growth which he has had for some time. The growth has become larger and looks like it has burst and is potentially rotting? Is there anything I can do for him? He seems happy enough and still feeds okay but I'm worried about him.
Thank you.

 

[JRS]

Sorry to hear about your fish. No personal experience with that type of wound. Normal wounds will typically heal given good water conditions although this looks like another cause. If you have a suitable holding tank you could remove it and try some treatments; otherwise catch it and try some topical antiseptic and back in the pond.

Some recommend an antiseptic treatment: https://www.fishlore.com/aquariumfishforum/threads/open-abscess-on-goldfish.426881/

There are various youtube videos that show minor surgery on goldfish if you are so inclined.