Fishman Island is the home of the fishmen and merfolk. It serves as an underwater gateway to the New World for those who do not wish to cross over the Red Line above. Though it is literally directly under the main seat of power of the World Government, it was however controlled by White beard, and then Big Mam. It is also notoriously difficult to reach, with only 30% of the ships surviving the journey. It is encased in a giant bubble, allowing visitors to breathe.

History......
Fishman Island came to be because fishmen on the ocean floor would gather at the only place where sunlight reached them. That place eventually became Fishman Island. The sunlight came from the roots of the Sunlight Tree Eve, which would absorb sunlight on the surface, and then send it down to Fishman Island via the tree's roots. Because it is the only way for any ship to enter the New World, for if people went through Mariejois they would have to leave their ship behind, Fishman Island was often visited by pirates passing through and the Marines chasing after them. When the Great Age of Piracy began, this problem escalated to extreme proportions. With this, many fishmen and merfolk were constantly kidnapped and sold off as slaves. However, when Whitebeard declared the island as his territory at some point in time, the problem was solved as attacking the island and its inhabitants would incur Whitebeard's wrath. As a result, the island was indirectly protected and peace was bestowed.

As Whitebeard died during the war, the island has lost its protection, but shortly after Big Mam gave her protection, in exchange of a large amount of candy every month, thus restoring peace. After parting ways with Luffy, Jinbe attempted to return to the island, but with it no longer protected with the death of Whitebeard and his abandonment of his Shichibukai position, he was forced to leave the island once again for his own protection. He left a message for prince Fukaboshi to deliver to Luffy once he finally reached the island.

When the Straw Hat Pirates arrived at Fishman Island, they were blocked from entering the bubble by the New Fishman Pirates who were unsure whether they should trust Luffy and would only let them pass if Luffy became an underling. To get past them, Nami planned to use the last bit of air left in Thousand Sunny's bubble for a Coup de Burst to shoot them through the bubble.

After the Straw Hats successfully passed through the bubble, their ship fell into a current and the crew scattered. Luffy, Usopp, Chopper, and Sanji reunite with Keimi at her house. Keimi then takes the four to Mermaid Cove where Sanji meets the objects of his dreams: beautiful mermaids. When the three princes of the Neptune House arrive to search for the pirates, the four pirates hide themselves to avoid arrest. Unfortunately, Sanji lost control of himself and suffered his greatest nosebleed forcing the four Straw Hats to reveal themselves. Usopp, Luffy, and Chopper beg for a blood donation to save Sanji's life, but Hammond shows up and explains that there is a law that prevents fishmen and humans from sharing blood. Hammond attempts to capture the four pirates, but Luffy is able to repel him and his companions. Keimi steals the princes' royal gondala and takes the four pirates to the town port.

At the town port, Keimi and the pirates takes shelter in Madame Shirley's Mermaid Cafe. Madame Shirley provides them a room in which they can treat Sanji. The group luckily comes across Splash and Splatter, a pair of okamas who happily agrees to donate blood to Sanji. After Sanji wakes up, he is horrified to see who his blood donors are. Chopper watches over Sanji as he recovers. Keimi tells Shirley to don't let Sanji see her and don't let him know that he is in the back room of the Mermaid Cafe. Keimi then takes Luffy and Ussop to the front entrance of the Mermaid Cafe where they reunite with Brook and Pappug. Pappug then invites the group to his mansion in Gyoverly Hills. Meanwhile Madame Shirley screams in the streets saying that she has forseen that a man in a straw hat will destroy Fishman Island.

Pappug, Keimi, Luffy, Usopp, and Brook arrive at Pappug's mansion in Gyoverly Hills. They enter the Criminal clothing store on the first floor where they find Nami complaining about the high prices. Pappug states that the pirates can have whatever they want for free. King Neptune arrives at the mansion and invites Luffy and his crew to his palace.