Wow, with views like that, who cares if there are fish in the pond. Just sit back and enjoy!!!
From your current photos, it looks like the water is less covered with weeds? I wonder if the rock scraping along the bottom is just releasing trapped air/gasses that's down in the muck. Have you considered taking a water sample to have it tested? How about throwing in a batch of FHM to see if they make it till spring? If they don't live, nothing will.
Is there any signs of the water ever running over the dam. I'm curious if you get flash flood type scenarios that might flush out fish life. Are you sure that's not a giant leech
