I've had this goldfish for about 5 years. Last fall it started to get large and round. We added more salt to the pond and tried some antibacterial/fungal treatments, but it didn't get better. The fish acted normally (swam around, ate, survived the winter), but last week it stopped eating and kept to the bottom of the pond. This morning, it was lying on its side at the bottom of the pond, and I actually thought it had died until I tried to remove it with a net. When the fish tried to swim away from the net, it couldn't swim straight and only spun around in a circle. It seemed extremely unlikely that it would live, so we euthanized it with clove oil. I'd still like to know what was wrong with it.
None of the other fish have visible problems. I suspected it might have been dropsy, but the fish survived with this problem for a long time and the scales never pointed away from the body like a pine cone.
Any help is appreciated, thanks.
None of the other fish have visible problems. I suspected it might have been dropsy, but the fish survived with this problem for a long time and the scales never pointed away from the body like a pine cone.

Any help is appreciated, thanks.