Clownfish appears to be bleeding

[Mike&Pam]

There is a red dot on the back of my clownfish. It looks as red as blood. Also, underneath that red dot beneath his gills appears to be bloody. This obviously is some sort of injury, but what could have caused it? Could it be my foxface, damsel, blue-legged hermit crabs, or jawfish? Obviously, it could be any of these. However, which would be the prime suspect?

Thanks.

Mike