I have had this fish in the tank for a couple of months and he has been fine up until a few days ago. He just stopped swimming and just stayed at the bottom of the tank. We noticed it looked like he might have got in to a fight because it look like he had a small mark on him near his tail. Today he is in really bad shape and looks like he has even changed to a lighter color. He also just got a large lump on his chest area. I'm not sure if he has some kind of disease or something else that could affect the other fish though all of them seem fine so far. See the attached pic of the lump. Any info would be helpful. Thanks
http://i46.tinypic.com/5v66o.jpg
http://i46.tinypic.com/5v66o.jpg