Fish-Man Island is a fictional underwater location in the One Piece manga and anime series created by Eiichiro Oda. It serves as the home of the Fish-Men and Merfolk, who have unique abilities and features adapted to life in the ocean. The island is located beneath the Red Line and is known for its vibrant coral reefs and diverse marine life. The island plays a significant role in the story, highlighting themes of discrimination and coexistence between different races. It is also a crucial stop for the main character, Monkey D. Luffy, and his crew, the Straw Hat Pirates, as they navigate their adventures in the New World.