Merman in My TubMerman in My Tub.

Merman in My Tub (Japanese: オレん家のフロ事情, Hepburn: Orenchi no Furo Jijō; lit. "The Circumstances in My Home's Bathtub") is a Japanese four-panel manga series written and illustrated by Itokichi. It has been serialized in Media Factory's Monthly Comic Gene magazine since 2011 and the chapters have collected into eight tankōbon volumes.