On one of the bass I caught this afternoon, I noticed his tail was a little odd. Right where the fin attached to the body, the body portion was red. The tail was a little frayed, but not bad, and the very bottom of the tail had some redness to it as well. I know their tails start to fray when they are fanning their beds, but I have never seen the area where the tail attaches to the body so red before. Does anybody know what causes this?

Looks like stress mark to me..from all that cold water..
Just a guess.