Fish-Man Jujutsu is another martial art that is practiced by the Fish-Man race, seemingly alongside Fish-Man Karate. It is a style that revolves around grappling and throw techniques.
Certain techniques can also be used to freely manipulate water itself, as if it were tangible material. How the Fish-Men are able to do this is unknown, but it provides them with a massive advantage in underwater combat. So far, only Jinbe and Hody have been shown using it. The other known user is Hack, although he has not been seen using any techniques. In the anime Aladine is a practitioner of this martial art as well.
Mizugokoro (水心,Mizugokoro?, literally meaning "Water Heart"): The primary technique of this style that the user initiates by first performing a bowl-shaped gesture with his hands (one hand over the other) while underwater right before giving the water itself around him a mighty yank. This allows the user to physically grab and redirect currents as if he were manipulating cloth. In the anime, Jinbe collects the water into a glowing, blue-white orb in his hands, he then swims off at high speed causing the orb to form a spiraling water current which he then throws to the surface. This move was first used within Impel Down's exterior bay in preparation for the Kairyu Ipponzeoi. In the Viz manga, and FUNimation adaptations, this is called Water Heart.
Kairyu Ipponzeoi (海流一本背負い,Kairyū Ipponzeoi?, literally meaning "Sea Current Lifter"): A technique used by Jinbe performed after Mizugokoro. He heaves the current upward, where it erupts from the ocean surface as a towering stream of water. This was first seen used in Impel Down's exterior bay in order to lift a makeshift raft onto a Marine battleship. Jinbe can generate multiple water streams like these if necessary. In the anime, Aladine used this against Charlotte Daifuku. "Ipponzeoi" is a kimarite (a winning technique in a sumo bout) where an opponent is thrown over the shoulder. In the Viz manga, FUNimation adaptations, this is called Ocean Current Shoulder Throw.
Murasame (群鮫,Murasame?, literally meaning "Pack of Sharks"): A technique used by Hody, he throws the water which takes the shape of a pack of sharks which bite his opponent. It is essentially a more powerful version of his Yabusame technique. "Murasame" is a type of rain; this technique simply uses homonym kanji to suit Hody's shark theme, similar to "Kirisame". This was first seen being used on Luffy and in the anime was powerful enough to briefly stand up against his Gomu Gomu no Elephant Gun. This is called Shark Pack in the Viz manga and FUNimation subs. Jinbe can also use this in One Piece: Pirate Warriors 3.
Uzushio Ipponzeoi (渦潮一本背負い,Uzushio Ipponzeoi?, literally meaning "Whirlpool Lifter"): A technique used by Jinbe, he grabs the arm of the enemy while facing the opposite direction and throws them over his shoulder, causing them to fall to the ground. This technique was shown to be effective against enemies much larger than Jinbe himself, including even Big Mom of the Four Emperors. In the Viz manga, this technique is called Fish-Man Judo: Whirlpool Shoulder Throw.
Hikishio Ipponzeoi (引潮一本背負い,Hikishio Ipponzeoi?, literally meaning "Ebb Tide Lifter"): A technique used by Jinbe that is similar to Uzushio Ipponzeoi, he blocks an opponent's attack, grabs them from somewhere in their body, and throws them over his shoulder, crashing them to the ground. It was first used against Who's-Who, grabbing him from his fangs. In the Viz manga, this is called Fish-Man Jiu-Jitsu: Low Tide Shoulder Throw.