VIENNETTA, a bit more information please. Please describe this "bump" in more detail. How big? Is it smooth looking like wax? Is it fuzzy like cotton? Does anything similar appear anywhere else on the fish?(like the pectoral or anal fins) Please, if you would, tell us a bit about your set-up? Is this a fish tank?(I assume it is) How big? Other fish? Any new addtions, fish or otherwise, to the tank? Have you added any medications or salt to the tank recently? Do you test your water? If so do you have the last readings handy to post? What is the temperature of the tank?
First thought as to what this "bump" may be... Carp Pox (fish pox). Please answer the queries above and we might be able to narrow it down a bit more than a quick guess.
Just a note: shubunkin's are not "coldwater" fish, goldfish are a "temperate" species - meaning they can live in a wide range of temperatures(as well as water conditions). Trout are "coldwater" fish, for example.
