Once Upon a Merman

All he ever wanted was not to be a Merman. To stop being the hatred Red-tail. One day he gets his wish and consequently ends up in the arms of his Mate... only there is a problem: his mate doesn't speak sign-language and Red-tail needs to learn Human language to tell his Mate that they have mated (Or the story of how Prince Voldemort got stuck with Merman Harry demanding his touch)