The Triplets and The Little Mermaid

S7 E13: The Triplets meet a prince whose father has arranged for him to marry a princess he doesn't love. The girls do everything they can to see that he falls in love with the Little Mermaid. The Witch of the Sea gives them a magic potion allowing the Little Mermaid to shed her tail and turn into a young woman. But in exchange for that, she loses her voice.