Mermaid Melody Pitchi Pitchi Pitch: Yuri

 Yuri is one of Gaito's Dark Lovers.  Like his other henchwomen she was originally a sea creature, in her case she was a Coelacanth.  She has the ability to control people by playing the piano.  In an unlikely turn of events, she and Hippo end up falling in love with each other.  Most of her barefoot scene's come form episode 25 of season one.