I believe there are 2 kinds of mucous plague, there's that hard black stuff that comes out in chips. I think that's really old stuff. Then there is what's called "ropes." I've gotten a lot of that. It tends to be 5 or 6 inches long but can be really long and it looks kind of intestine shaped. I'm pretty sure its just "newer" plaque. Mine is brown but I wouldn't say that dark red is impossible. If you feel okay I don't think you have anything to worry about. Maybe the plaque pulling loose caused a bit of light bleeding because Oxypowder is pretty strong. Think if you just ease up for a few days you'll be fine.