From Bulbapedia, the community-driven Pokémon encyclopedia.
(Japanese: ホタチ島 Hotachi Island) is the second island Ash, Iris and Cilan visited during their travels through the Decolora Islands. This island is inhabited by Oshawott and Dewott.
On the island, Oshawott fell in love with a female Oshawott, nicknamed Mijuka, who seemed to be a queen. The island hosts a traditional competition related to Oshawott and its evolved form. In order to get her attention, Ash's Oshawott entered the tournament, gaining a rivalry with a Dewott. After wining the battle, Ash and his friends got on the boat again to continue their travels.
Pokémon seen in Hotachi Island