Golfish lumps!

Question
My goldfish has just developed a tumor like growth just before his tail fin. The lump looks like a fluffy cloud and is the same colour as the fish, not white or grey. What could it be and how can I treat it?

Answer
hello,

This could be in fact a tumor or cancer, however without looking at the fish I can give a correct diagnosis. If you could please attach a picture or give more information that would be great. However I can tell you to separate it from other fish and to do a 10% water change every other day for about 2 weeks to try and get anything bad out of the water, unfortunately there is not much you can do if it is ether a tumor or cancer. I am sorry I cant help much more without a picture or more information.

Thanks alot,
Michael M.