[SOLVED] Horror movie about infected lake water that turns teens into fish?

And maybe "Beneath Still Waters" (2005) ? Do you remember something more?
https://www.imdb.com/title/tt0371572/plotsummary/?ref_=tt_ov_pl

"Two boys make a pact to do something brave, crazy and dangerous. They will see their town one last time before a man-made lake floods it forever, burying it under the deep lake. Everyone's been evacuated - just the church, the homes, the abandoned shops remain. Only the eerie buildings...still hiding secrets that no one suspects. The two boys walk through the doomed ghost town. But the boys discover that the town isn't quite deserted. And they are trapped as a massive wall of water crashes down on the town. Time passes, and the whispered secrets of the town have been long forgotten. But now, fifty years after vanishing, the sunken town comes alive again. A boy vanishes swimming on a moonlit night while his girlfriend looks on. The very shoreline turns hungry, pulling people into the water. And below-below where it's incredibly cold and dark, the sunken town waits. Because beneath still waters something ancient now stirs. A forgotten legend lives again. Half a century ago they thought they had buried this horror forever. But you can't kill what was never really alive. And the massive stone walls of the Dam must soon burst and what was an incredible myth, will become a deadly reality."

Other possibility is "Weaverfish" (2013).
"After spending the night partying at a condemned river creek, the atmosphere is soon lost for quiet teenager Reece and his friends. Headaches and heartaches give way to a terrifying race back to civilisation as a grossly disfiguring virus takes hold on the most vulnerable."