Fish-Man Island

Biodata

Feature	Information
Name	Fish-Man Island
Original Name	鱼人岛
Affiliation	Ryugu Kingdom; a World Government member nation; later protected under the Whitebeard Pirates' flag 16 17 38
Status	Active
First Appearance	Chapter 12

Geography and Environment

Fish-Man Island lies 10,000 meters beneath the sea, built around the roots of Sun Tree Eve and enclosed within an enormous, gourd-shaped bubble membrane. Sun Tree Eve carries sunlight and oxygen down from the surface, allowing the island to sustain fields, coral growth, and land-like districts beneath the ocean. 13 40

• The island's translucent membrane encloses beaches, coral, public waterways, residential areas, and an internal ocean. 13
• An official passage through the bubble membrane allows coated ships to enter, then travel through internal waterways to the ship district. 13
• The outer coating is a defensive layer: ships forcing entry lose their own coating and can be left suspended and wrecked in the air between layers. Kaido breached both layers by force. 24
• Ryugu Palace stands in the upper sphere of the island and serves as the royal seat, with transportation routes connecting it to the rest of Fish-Man Island. 16
• Coral Hill is a prosperous southeastern district and home to the Mermaid Cafe. 13
• Sea Forest, northeast of the Fish-Man District, is a coral-filled ship graveyard containing countless wrecks. 22
• The Fish-Man District directly faces the deep sea and is outside Fish-Man Island proper, making it difficult for outsiders to search. 17

Population and Society

Fish-Man Island is home to fish-men and merfolk, who coexist under the Ryugu Kingdom.

• Fish-men possess beast-like traits and arm strength stated to be ten times that of ordinary humans. 13
• Merfolk have human upper bodies and fish tails, are exceptionally fast swimmers, communicate with ordinary fish, and commonly form close bonds with sea creatures. 13
• Children can inherit fish lineages from throughout their ancestry rather than solely from their parents; Neptune's family includes several distinct marine bloodlines. 23
• Species discrimination among island residents is described as rare, though the pirate-descended Vander Decken Family is widely despised. 23
• Fish-men and merfolk have long been hunted and enslaved by pirates and Marines despite the island's status as a World Government member nation. 17

Government and Defense

The Ryugu Kingdom is Fish-Man Island's sole established government, ruled by King Neptune and the royal family from Ryugu Palace. 16

Position / Force	Role
King Neptune	Ruler of the Ryugu Kingdom and head of the royal family. 16
Queen Otohime	Neptune's wife and a supporter of closer relations with humans. 16 17
Neptune's Army	The kingdom's military force; Jinbe is its strongest member. 20 21
National Preceptor / Advisor	Mobius accepts this position after advising Neptune on alliances and development. 18 21

Fish-Man Island's geography provides some protection, but Neptune acknowledges that it lacks sufficient high-level fighters to resist major outside threats. Destroying the outer bubble would make the island far harder to enter, but would also devastate the kingdom itself. 17

Economy and Transportation

Fish-Man Island's inhabitants use sea creatures as mounts, taxis, and work partners; most public waterways are traversed by creatures enclosed in bubble membranes. 13

• Sea creatures are raised as family companions as well as transportation partners. 13
• The island's deep-sea resources include pearls, coral, Sun Tree branches, sea-beast meat, oil, bones, and organs. 34
• Sun Tree Eve's light permits the cultivation of staple crops such as rice and noodles. 40
• Mobius proposes using fish-men and merfolk's underwater mobility to establish shipping routes through Whitebeard territory, with Fish-Man Island exporting its unique resources in exchange for protection and employment. 17
• He also proposes a mermaid-themed ocean restaurant as part of future commercial cooperation. 21

History

Fisher Tiger Incident

Fisher Tiger's assault on Mary Geoise and liberation of slaves places Fish-Man Island at the center of international attention. The World Government issues Tiger a bounty, while Whitebeard, Kaido, and Charlotte Linlin each take an interest in him and the island. 12 17

Shyarly foresees both Tiger's death and a coming crisis for Fish-Man Island. Her warning brings Mobius to Ryugu Palace, where Neptune, Otohime, Jinbe, and Mobius begin discussing how to protect Tiger and the kingdom. 15 16 17

Whitebeard Protection Plan

Mobius advises Neptune to form a long-term commercial alliance with Whitebeard rather than rely on a simple transaction. The plan would combine Whitebeard's territorial protection with Fish-Man Island's underwater transportation, labor, and deep-sea resources. 17

Neptune appoints Mobius national preceptor after accepting his counsel and his stated Navy affiliation. 18

Kaido's Invasion

Kaido forcibly enters Fish-Man Island by breaking through its bubble defenses, causing widespread destruction and overwhelming many residents with his Conqueror's Haki. 24

Jinbe confronts Kaido but is defeated. Mobius battles Kaido in and around Ryugu Palace, using the island's golden dragon statue and the Sea Forest's Poneglyphs as part of his defense before driving Kaido from Fish-Man Island. 25 26 27

The invasion is followed by clashes involving Whitebeard and Harald, King of the Giants. Their battle shakes Fish-Man Island and churns the surrounding sea for nearly a day. 30 32

Whitebeard Flag and Regional Cooperation

After the crisis, Neptune formally requests Whitebeard's protection, and Fish-Man Island is placed under the Whitebeard Pirates' flag. Whitebeard crew members begin openly visiting the island. 38

Fisher Tiger later returns and agrees to help strengthen Fish-Man Island alongside Mobius, Neptune, Whitebeard, and the Giant Kingdom. The kingdom also agrees to receive homeless people and former slaves rescued from Mary Geoise. 39 40

Notable Sites

• Ryugu Palace — Royal residence of Neptune's family and the center of the Ryugu Kingdom's government. A golden dragon statue sits atop the palace. 16 27
• Mermaid Cafe — A Coral Hill establishment where Shyarly works as a fortune-teller. 13
• Sea Forest — Coral-covered ship graveyard northeast of the Fish-Man District; formerly held one gray and one red Poneglyph. 22
• Fish-Man District — Deep-sea-facing district associated with Fisher Tiger and many drifters. 11 17
• Ship District — Docking area reached through Fish-Man Island's official entrance and internal waterways. 13

Relationships

• Ryugu Kingdom — Fish-Man Island's governing state, ruled by Neptune from Ryugu Palace. 16
• Fisher Tiger — His attack on Mary Geoise triggers the island's political crisis and draws powerful outside forces toward it. 12 17
• Whitebeard Pirates — Provide territorial protection after Neptune requests Whitebeard's flag; also assist Fish-Man Island's trade and refugee efforts. 38 39
• Giant Kingdom / Elbaf — Enters a cooperative regional arrangement with Fish-Man Island and the Whitebeard Pirates. 32 39
• Kuja Island — Cooperates in efforts to locate abducted Kuja warriors and assist liberated slaves. 36 39
• World Government — Fish-Man Island is formally affiliated with it, but its people remain vulnerable to enslavement and receive little protection. 17
• Vander Decken Family — A pirate-descended family regarded as outsiders and despised by many island residents. 23