Thanks everyone. Just to add (if it makes any difference), the fish were part of a swarm that was loitering under a small bridge. I'm not sure how much vegetation the lake actually has, but it is a large-ish lake which is quite popular with a large variety of ducks (and Savi's Warbler, and Thrush Nightingale, etc.). There were also two Goosander circling the swarm. The pictures were taken in calmer pauses between gusts of wind that would've blurred them even more.