I have been gone for a couple weeks and just came home to find one of my angelfish with what looks like a parasite. It is protruding like worms or something. None of the other fish in the tank seem to have it and there have been no new fish (or anything else for that matter) added to the tank in over 2 years. I have been totally free of disease or parasite problems over the last 3+ years so I am clueless as to the different varities. What is it and what do I need to treat with? Thanks for your help.