Merman Combat

Merman Combat (人魚柔術（マーマンコンバット）) is a fighting style used by the merfolk. It is used underwater and involves manipulating the water with their hands as if it were something tangible to use for long ranged attacks. It is in essence, the merfolk equivalent of Fishman Karate.

Techniques

 * Ultramarine (ウルトラマリン): Used by Neptune and Fukaboshi, the user grabs the water with their hands, similar to Jinbe's Mizugokoro, and then hurls it forward in a mighty, extremely large torrent that blasts away his opponents with great force. "Ultramarine" usually refers to a shade of blue and got its name from "ultramarinus", literally meaning "beyond the sea". In One Piece: Gigant Battle! 2 New World, Neptune condenses the water in the atmosphere into his hands as a sphere and launches it forward as a massive torrent.
 * Koin Ryusui So ( 光陰流水槍 Kōin Ryūsui Sō?, literally meaning "Flying Time Spear"): Used by Fukaboshi , he initiates this attack by spinning his trident rapidly. He then lashes forward and rapidly slashes his enemy with great strength. This attack is powerful enough to defeat some of the New Fishman Pirates ' sea monsters. In the FUNimation subs, this is called Spear of the Ages.
 * Ryugu Romon ( 竜宮楼門 Ryūgū Rōmon?, literally meaning "Dragon Palace Tower Gate"): Used by Ryuboshi , he moves both of his swords forward rapidly, slashing his enemies numerous times. This attack was strong enough to defeat some of the New Fishman Pirates' sea monsters. In the FUNimation subs, this is called Dragon Tower Gate.
 * Shitchin Banpo ( 七珍万宝 Shitchin Banpō?, literally meaning "All the Treasure"): Used by Manboshi , this is a powerful slashing attack, performed with both hands on the sword's hilt. It was strong enough to defeat some of the gigantic sea monsters sent against the three princes by the New Fishman Pirates. In the FUNimation subs, this is called Seven Great Treasures.

Trivia

 * The "Ultramarine" technique resembles the Kamehameha technique, an iconic and powerful energy wave from the Dragon Ball series.