Hope someone can shed some light on this dilemma. I found this bluegill laying on the bottom at the shoreline of my pond. He wasn't dead but barely moving. I revived him a bit and he swam about 2ft and laid over on his side and sank to the bottom. Upon further inspection I saw that the base of his tail was bright blood red. There was no apparent loss of fin but since he was dying and the color of his tail fin was of concern, I decided to remove him from the pond. I have pictures but can't seem to find a way to attach them. I can email them to anyone.

Hard to tell even with pics. The bloody tail could be a male fanning a nest. I wouldn’t worry about it unless you see a lot of them.

I looked for that possibility but couldn't find anything close to a nest. The fact that it was lying on it's side on the bottom concerned me.

Obviously, the fish was having a hard time. I have known fish in aquariums to run into the glass or decorative rocks and knock them selves silly. Some would recover while most did not. Your fish may have also been sick to some degree and was on it's way out. The bloody tail could be a result of the illness or a wound from a bird or larger fish attack OR an infection caused from the lack of movement and lying on the bottom. Hard to tell really...I would have removed the fish as well. Keep you eye open for more of the same, but I bet it was a one time occurrence.

I'm hoping you're right Quarter.