The mucous casing hanging from the anus is also indicative of TB.It's hard to tell from the pic, but it looks like either an aero/pseudomonas infection, or a nasty case of fish tb. I'm leaning more towards tb since aeromonas ulcers don't tend to protrude from the body so much. The stringy white poo also points to signs of internal infection. In any case, here are a few websites to get you started on possible treatment options.
http://weloveteaching.com/puregold/disease/symptom/byname.htm#aeromonas
http://weloveteaching.com/puregold/disease/disease.htm
http://www.aquaticcommunity.com/disease/tbc.php