Bite or illness?

[Smoke to Fire]

Hi, sorry I dont have any pics as of just yet to post up, but camera has taken a turn for the worst. Anyways, today I noticed that one of my discus appeared to have what looked like a small area about mid way down the body towards the fin on top (sorry dont know the proper term). When I got closer and looked I could see two areas close to each other, about as big around as the circumference of a ball point pen. Another one of my discus showed an even larger area lower on the body roughly 3/4 dime size. At first it looked like it was white but now kind of appears more like the clear coat coming of a car (for lack of a better analogy). The body is metallic except for the dull spots on the two fish. I have not added any new fish to the tank in approx one month, and water params are 0 ammonia, 0 nitrite, 10 nitrate, temps sitting at 86 degrees. Water change is done 50% every 6 days on the dot. Carbon changed every two weeks and sponges monthly in rotation. Filters are a penguin 350 biowheel, and an aquael unimax pro 150 canister with uv light, light on for approx 3 hours following water change. The current load in the tank is 11 cardinal tetras, 4 discus, 1 bamboo shrimp, and 2 bristlenose plecos (newest fish in there, approx 1 month).
So question being, does this sound more like a disease that I should be worried about? or more like the plecos have taken a liking to the side of my discus? I will try to get some pictures up later tonight if I can get another camera somewhere. I read that the shrimp wont bother anything at all so I doubted it would be him, though who knows. This just appeared today.
Thanks for any help you can provide.
Post pics later hopefully.

[ShinShin]

With this little info, I would suspect a gram negative bacteria. Treat with an antibiotic either specically for gram negative, or a broad spectrum if you can't find one.

Mat