"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.

The Nixie, Nixy, Nix, Näcken, Nicor, Nøkk, or Nøkken are humanoid, and often shapeshifting water spirits in Germanic mythology and folklore.