This Boy Caught a Merman is a 30 minute long OVA (Original Video Animation) that was both Subbed and Dubbed in English about a teenage boy and the merman that saves him from drowning. After unthinkingly diving to save a photo of his grandfather.
Shima, a teenage boy who had just lost his grandfather whom he always stayed with went to the ocean one day with his grandfather's memorial plate. Dropping it in the water on accident, he dives in after it although he can not swim. Shima is saved by a merman who he ends up living with and naming "Isaki". Isaki loves Shima, but leaves, thinking that he is no longer needed when Shima makes new friends at school. Shima chases after Isaki, and jumps in the ocean, only to be saved by him again, and Isaki's feelings are revealed.