***** Attention Spoilers******
So Shirley came by and spoke about her vision/prediction saying that the one who would destroy the Fishman Island is not Hordy buy Straw Hat Luffy.... When this prediction was made by Shirley in chapter 631, I was very confused. Although I linked it to the feeling that when Hordy and Luffy clash, the fighting would be intense that Luffy would end up destroying the island with some technique... But after reading chapter 632, I feel like I am seeing a new light on this prediction, so here goes...
In my opinion, I think Shirley is referring to the Rebirth of the Fishman Island. When she says Straw Hat Luffy will destroy the island, I think she meant the old ways and struggles of the Fishmen would come to an end when Luffy goes head to head with Hordy and this will bring the fall of the Fishman Island struggle with Humans. After this, a new Fishman Island will be born where the Fishmen will come to understand that there are some humans that do care and this will give them a new perspective on the spieces called Humans. This will however, only happen because Luffy will be involved.
This is just my opinion since reading the last 2 chapters. Please comment on this and post your own opinions on what you think of shirley's prediction. It would be interesting to know what you folks are thinking about it.