My goldfish appears to have a tumour growing on its back, this has caused the dorsal fin to split and the tumour has grown around it but doesn't appear to cause any discomfort, however, this morning when I fed them (I have 2 fish in a 3ftx1.5ft tank) I noticed the tumour has been eaten by the other fish and wondered if A. will this cause the healthier fish to catch a tumour? B. I'm worried my fish with the tumour is in pain because it's the tumour is being picked at.

I've researched a few sites and what I can find is that there is no way to remove the tumors, and the fish can live with them on their bodies and no be in any discomfort as long as it doesn't effect it's breathing or eating or bowel movements.

I would say that the other fish is trying to rid your sick fish from it's environment, and I can only assume that anything being picked off it's body would cause discomfort. You could give him a burial at sea or transfer to a separate tank. From what I have read, it seems the fish's life span will be shortened.

Something's I have read said that malnutrition and dirty tanks are a contribution to growths and tumors.

Thanks for your reply. Ive been watching them all day and the one with the tumour doesn't seem to be in any discomfort at all, apetite is good, they get a quality feed in the form of Tetra Goldfish sticks as well as foliage which they ravage. The other fish without the tumour is picking ONLY the tumour off and not attacking any other body part, they get on really well and don't fight at all. I keep an eye on their water ph and test it weekly as well as regular gravel cleans and the filters get done also. Il keep an eye on it and won't let it suffer in any way but here's hoping it doesn't get worse, many thanks, steve.

I'm not very knowledgeable about fish, but my dad was, and I remember a fish with a tumor in his tank.

Like yours, the other fish picked at the tumor. It was stressful to watch. My dad said that the tumor is dead growth, in other words, the tumor itself doesn't produce pain, the skin and tissue is dead, and it doesn't hurt to have it picked at.

This is just based on what my dad told me and he knew his fish. Sadly he didn't pass that knowledge down to me, or I didn't listen well enough. ;)

If you notice that the fish is in pain I would definitely think about getting another tank and making him a solitary fish.

Good luck.

Good luck Steve! :)