Pokemon - episode 61 - 02 Sep, 1998

Upon returning to Cerulean City, Misty is asked by her sisters to help out with a new underwater show. She decides to help for this underwater play with her Pokémon, but Team Rocket arrives and try to ruin things. At the end of the episode, Misty leaves her Starmie and Horsea with her sisters to assist in further shows. (Source: Wikipedia)