Kenkou Zenrakei Suiei-bu UmishouEpisode 4

Kaname Okiura, a student of Prefectoral Umineko Shougyou High , joined the school's swimming club in order to learn how to swim, but the club is filled with weirdos, let alone who can teach him swimming. Then, a sunny, happy-go-lucky girl named Amuro Ninagawa who transferred from Okinawa joined the club. Her extraordinary underwater speed and unorthodox swimming style surprised every club member, especially Okiura, because she reminds him of a mermaid-like creature he saw only once in his early childhood.