In this aquarium, there isn't a single ordinary fish. Instead, what swims in the tanks are—. Sotaro, an aquarium worker, spent every waking moment searching for new homes for the animals after the aquarium’s closure was decided. In the midst of his grueling life, his consciousness became hazy, and he woke up in another world!? Despite being exiled to a remote island for having a "useless skill," Sotaro gets help from a Legendary Sea Dragon (Monster Girl), and his quest to create his ideal aquarium begins now!