Rosy Life Riders

The Rosy Life Riders (人生バラ色ライダーズ, Jinsei Bara-iro Raidāzu), formerly called the Flying Fish Riders (トビウオライダーズ, Tobiuo Raidāzu) were a kidnapping gang from around Fishman Island. They ride on flying fish, hence their gang's name. Their leader is Duval. With the handles on their flying fish and the way they dress, they resemble a biker gang. Since Duval's face alteration, however, the gang was reformed into the "Rosy Life Riders", and their purpose changed.

Flying Fishes
The flying fishes that the gang members ride on are roughly as big as dolphins, and can stay above water for five minutes. Although these fishes can fly in air, they are much faster underwater: in fact, their speed in water is second only to merfolks. The fishes have motorcycle handles, pedals, seats, and some other cosmetic designs installed on them, so the riders can ride them with ease. The riders also have underwater oxygen masks prepared alongside their seats, in case they need to dive into the sea.

While the gang members ride the flying fishes, their leader Duval instead rides Motobaro, a bison with special breathing apparatus that allows underwater travel.

Sabaody Archipelago Arc
The Flying Fish Riders were first seen helping the Macro Fishman Pirates kidnap Hatchan, a former member of the Arlong Pirates, and holding him in their base. In order to save their friend and assist his partners Keimi and Pappug, the Straw Hats fought against and subsequently defeated them. Sanji completed the matter by rearranging leader Duval's face, allowing him to see the fault of his ways and allowing them to become friendlier with the Straw Hats and give up on the slave trade. After Keimi was captured by other slave traders on the Sabaody Archipelago, Sanji requested their assistance to help find her and get her out of her predicament. To which they do by finding the Straw Hats on the island and flying them to the auction house were Keimi is being held. After that incident they part ways, promising to help the crew while they were still on the island.

Later they're seen watching over the Thousand Sunny so it can be coated, unaware that the Straw Hats had been knocked off the island.

Post-War Arc
They are seen again still guarding the Thousand Sunny and prevented a group of thugs from stealing the ship. They then prepare to face off against Shichibukai Bartholomew Kuma.

Straw Hats Return Arc
2 Years Later

They are seen surrounding Duval, and heavily bandaged, presumably due to helping their boss defend the Thousand Sunny.