Luffy does not destroy fishman island however it is a possibility that it could happen considering that the islands of Rafteel(where One Piece is located supposedly) and Marie Jois (the tenryubito homeland) are possible arcs that could bring about a calamity strong enough to make that happen.

Right now it's simply too soon to say.

Luffy does not destroy Fishman Island. However, it is a possibility that it could happen considering that the islands of Raftel (where One Piece is located supposedly) and Mariejois (the tenryubito homeland) are possible arcs that could bring about a calamity strong enough to make that happen.

Right now it's simply too soon to say.