Watch Jezebel (1978)
Dyesebel is unique among the merfolk for she is the only mermaid born of human parents from the surface world. A mermaid from birth, she is shunned by the superstitious due to her physical form. After her father is killed by an angry, superstitious mob, Dyesebel is taken to the ocean by her mother where she is sent into exile since her chances for survival are greater there than on land. The young girl-mermaid is found by Banak who adopts her and takes her to their kingdom where she is welcomed into their community.