The cory looks like it got cut up by some jagged rock or something.
I think this is it.( copied from emergency forum.)
Septicemia: A fairly rare to common in all tropical and coldwater fish. It is caused by bad tank conditons and is very hard to cure if not impossible. Bacterial Hemorrhagic Septicemia can be diagnosed by red streaking of the fins and body and once this disease progresses, ulcerations and body sores start to appear. There is significant loss of appetite, lethargy, loss of motor functions in the later stages of the disease.
Treatment: I recomend using Oxytetracycline Hydrochloride Powder obtained from a vet to cure this disease.
Then there is the all too common (at least I have noticed in Goldfish) Anchor Worm.
Diagnosis: The fish scrapes itself against objects, whitish-green threads hang out of the fish's skin with an inflamed area at the point of attachment.
(copied here from a web page) Anchor worms are actually crustaceans. The young are free swimming and borrow into the skin, go into the muscles and develop for several months before showing. They release eggs and die. The holes left behind are ugly and may become infected.
Treatment (copied from web page) The anchor worm is too deeply imbedded to safely remove. Treatment can best be done with a 10 to 30 minute bath in 10 mg per liter of potassium permanganate. Or treat the whole tank with 2 mg per liter, but this method is messy and dyes the water.
/www.fishforums.net/index.php?act=ST&f=22&t=67680
