Papaneel is a fishman who lived on Fishman Island at the same time as Otohime.

He was first shown robbing to get money for his family. When Otohime stood in his way, Papaneel tried to shoot her. Otohime dodged his shots and slapped him. After knocking him down, Otohime lectured him about the errors of his ways. Touched by Otohime's concern, he swore to change his ways and rectify his life.

First Appearance: Chapter 621; Episode 540

His name was revealed in One Piece Blue Deep Databook— page 216.

(Source: One Piece Wikia)