Sea Heart

Naomi's father is a sea biologist and has been offered a job in California. Once there, Naomi finds that she feels like she somewhat belongs. Like being closer to the ocean makes her feel alive for once in her life. Until she starts to control water and hold her breathe for extended periods of time.
Three girls Belle, Felicity, and Vivianne notice this and help Naomi realize that she is a mermaid and show her the wonders of the ocean, as well the civilization that lives there.
However the mermaids and merwomen have a bad feeling about Naomi and are reluctant to accept her, especially if the sirens are watching her so carefully.
....Slight blood and grotesque warning. If you are scared of the thought of the depths of the ocean, read at your own risk....