I was wondering if it's possible for goldfish and koi to get ick. I've never really heard of it happening but I was wondering if its possible or not. Picked up 2 koi out of the same tank from the lfs, but a few days later one started to not use its front right fin. The fin looks thicker and has a redish tinge to it and he refuses to use it at all, also his color went from a vibrant black to a dull black and had a few white looking things hanging off the right side and around his gills (kinda looked like a small worm but not quite.) Started adding melafix to it about a week and a half ago and still no change. A few days ago I picked up a couple of goldfish and put them in with the koi, now the goldfish have ick on them from no signs from before. Is it possible for them to get ick or is it ick and I need to switch what kind of treatment I'm doing? 
Onna

Onna