Jinbe

The Arlong Pirates used to be part of Jimbei's crew, but he left to become a "dog of the government", otherwise known as the Shichibukai. Although Arlong was referred to as Jimbei's equal, the odds of one of The Shichibukai being equal to a pirate with a bounty of 20,000,000 belli is very unlikely. It is therefore speculated that Arlong was Jimbei's equal before he left or that it refers rank is based on his growing up with Jimbei on Fish-man Island and not on actual strength. Although the only known reason (and there may be others in addition) is that Arlong was paying Nezumi to keep him under raps, thus keeping his bounty at a lowly 20 Million when he desrved a much higher bounty. Jinbei is speculated to be a Whale Shark fishman, as 甚平鮫 jinbei-zame means "whale shark" in Japanese.