If they are still eating I've had good luck with Melafix and Maracyn. Bleeding is nearly always bacterial. I used to work at a LFS and they used to sell anti-bacterial foods but I don't know if that's still on the market or not.
Use a combination of maracyn 1 and 2. They are safe to use together and so will combat both gram-negative and gram-positive bacteria. In the freshwater forum I used to frequent (and really should get back to), I learned this condition is called hemorrhagic septicemia (broken down, it means a blood infection that causes bleeding.)