I have been fishing 30+ years (mostly for bass/bluegill/catfish) and I have noticed that sometimes the bass have "red spots" in their mouth. It's not like a sore spot where they been hooked and released but something like if you had a sore throat. My father always told me when I was younger and one of us would catch one like this that "it's the change in weather. They have "sore mouths" so they will be harder to catch". I don't know if this was true or not but it did seem to be tougher to catch them. My question is this. Does anyone know what causes this and what it is?