This is a German folktale about a water spirit known as the Nix of the Mill-Pond. The Nix is a mischievous creature that lives in the depths of a mill-pond and is said to lure people to their doom. The story follows a young man
From Wikipedia
"The Nixie of the Mill-Pond" is a German fairy tale that tells the story of a man captured by a nix and his wife's efforts to save him. The Brothers Grimm collected the tale in their Grimm's Fairy Tales (1857) as tale number 181. A note in the volume indicated that it was current in Upper Lusatia when the story was collected. Andrew Lang included a version in The Yellow Fairy Book, citing his source Hermann Kletke and titling it The Nixy.