My Bride is a Mermaid (2007)

Cast

Takahiro Mizushima, Haruko Momoi, Ayumi Tsunematsu, Atsushi Imaruoka, Takehito Koyasu

Overview

Nagasumi's in hot water after a beautiful, young mermaid named Sun saves him from drowning. The deep-sea sweetheart's dad is a merman yakuza prone to executing anyone who learns his family's scaly secret! Luckily, there's a catch - if Nagasumi agrees to marry Sun, he just might avoid sleeping with the fishes!