My Bride is a Mermaid

My Bride is a Mermaid (2007) is a comedy, animation, sci-fi & fantasy with 1 season, rated 6.5/10.

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!