A Shark in the Public Pool is the 32nd episode of the Katekyo Hitman Reborn! anime.
Tsuna has to swim 15m in school, but, being unable to swim, he is trained by Yamamoto, Gokudera and Haru in the public pool. Everyone has their own method, and they decide to compete to see who can get Tsuna to swim the furthest. Reborn interferes this time with a Vongola dolphin that has a dangerous personality.