Yesterday I went to a local pond/koi store and found a gorgeous solid platinum butterfly koi, over a foot long, for 75 bucks! At least in my area this is a really great deal. When I told the lady I wanted him, she said he's a great fish but she had to give me a heads up. On his side she pointed out a small mass I didn't see when I checked him out. She said she'd noticed it when he was just a little guy four years ago and tossed him into the mud pond they had (where they put the fish not quite right to sell, but too healthy to put down) after they drained it, they put him up for sale as it hasn't grown or caused him any issue. It's not open, it's almost not noticeable (and certainly not when he's swimming around and not in the tub she showed me him in) so of course I took him home I've named him Spooky and he's already fairly friendly. I also took along his 16-17" friend who was a real deal because of one undersized pectoral fin. I have a soft spot for the "weird" ones I just want to make sure there's nothing special I need to worry about because of this guys tumor. Do they get infected or become a sore easily? It hasn't grown in 4 years... is it possible it could begin growing again?

Thanks in advance

I'm surprised she spotted a tumor in a fish that is only 12" now, four years ago. WOW! That sure is some eye. Regarding your fish I really would not worry to much. It would not manifest itself by showing an ulcer...but would more than likely cause organ failure if it was really a problem. If its been four years you should be OK.
I also would not plan on the fish getting any larger if it is already over 4 years old and only 12", but maybe you'll be the lucky one. You never know when you put them in differing water conditions and parameters.

Thanks for the reply Well, she said that it has been the same size for that long. Apparently when he was a little guy it was much more obvious- he's grown, the tumor hasn't. I don't expect him to get very large (he is slim between the pectoral fins, I've been told this is a fairly good indication of what they'll grow up to be) but he seems healthy as can be. But, I'll still feed him lots of good foods to try to encourage any growth he may be capable of.

pics?