After Luffy's explosive entrance, he is stopped by Arlong's men. Luffy ignores their attempts at diplomacy and throws a huge punch into the face of their Fishmen captain, Arlong. Luffy cannot forgive Arlong for making Nami cry, as he still considers her as his navigator.
After this declaration of war, the fishmen attack Luffy. However, they are easily knocked back by Sanji, who had also entered the place alongside with Zoro and Usopp. Hatchan, enraged after Zoro tricked him, threatens them that they will be the meal of his pet Mohmoo. When the giant sea cow appears, he still bears the wounds of his previous encounter with Luffy and Sanji, and is reluctant to attack. To the surprise of the fishmen the Straw Hat Pirates are unimpressed with Mohmoo's appearance. After being threatened by Arlong, Mohmoo attacks the Straw Hats. Luffy grabs his body and launches it to knock back most of the Fishmen pirates.