1.146 out of 5 from 36 votes
According to legend, on a midsummer night the blue butterfly fish appears in a dragon's mouth near a tropical paradise. Ushio, Sara and their friends are in search of the fish, but even after multiple dives they're unable to find it. However, soon after Ushio and his friends encounter two women who seem to know about the blue butterfly fish. Will Ushio find what he's looking for?
Both anime are about underwater adventures and have interesting animation. B.B. Fish has much more of an interesting plot since it's a full on ova opposed to Natsuyasumi no Osakana which is just a music video but if you like water fun check either out.