The destruction of Fishman Island is an intriguing plot point that is yet to be resolved in One Piece. This plot was first introduced by Oda during the Fishman Island Arc, where a lot of the residents of the place deemed Luffy an enemy due to Madame Shyarlys prediction. Of course, her predictions are never wrong, which means at some point later down the line, Luffy will be responsible for the destruction of Fishman Island.