My Bride is a Mermaid
瀬戸の花嫁 (original)
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!
Starring Ayumi Tsunematsu, Atsushi Imaruoka, Takehito Koyasu, Noriko Rikimaru, Masahito Yabe, Noriko Namiki, Tomoko Kaneda, Natsuko Kuwatani, Tesshou Genda, Kenta Miyake
Watch "My Bride is a Mermaid" on Amazon released in 2007. It's a comedy and animation show, and has a rating of 7.2 out of 10 from Imdb which is usually fine for this kind of show.