Ever After (1970)

Belly sinks further and further down into the depths of a mysterious underwater garden. Above water, she is bullied at school for not speaking the language and already having her period. At home, her mother gives her nothing but tough love. Down below is the only place she feels free. But before she can truly live and breathe in this dark fairy tale realm, she must grow the fins of a mermaid, which requires a very painful sacrifice.