In "One Piece," the straw hat has nine members which is Monkey D Luffy, Roronoa Zoro, Nami, Ussop, Sanji, Tony Tony Chopper, Nico Robin, Franky and Brook. During Fishman Island arc, Monkey D Luffy invites Jinbei to join their crew but Jinbei declines. Jinbei said he wants to join them but he mentioned that he needs to do something first.
Jinbei is the strongest fishman so far in "One Piece" and he is a Master of Fishman Karate. He is skilled enough that he became a black belt of this arts since he was still a child. With fishman Karate, Jinbei can knock away many opponents at once, manipulate water like it is a tangible cloth.
Some of his skills such as strike don't required to physically hit his opponents as the water particles in the air will blow away opponents. Jinbei also said that with Fishman Karate, it allows him to control all the water within his vicinity including water in a person's body. Jinbei also shows great physical ability in "One Piece" as he threw away a giant fishman with just one kick.
Jinbei also has a high tolerance of pain when he stops the Magma punch of Akainu with his bare hands that badly burned Jinbei's hand. Jinbei is also a former shichibukai or the seven warlords of the sea in "One Piece" and he let go of this position as he is against the execution of Portgas D Ace. As a fishman, he is very familiar with the sea that's why he can be he helmsman of the Straw hat pirates.
During the escape in Impel Down in "One Piece", Jinbei is the one who is steering the ship and he show's great skills maneuvering an unfamiliar ship. Currently Jinbei is breaking ties with Big Mom and this could mean that after he break ties he would join straw hat pirates. There is no helmsman yet in the straw hat pirates and Jinbei can fill that position.
In the current story-line in "One Piece", Jinbei is not done breaking ties with Big Mom as the consequence of leaving her crew is having a part of his extremities or his head. Now, we are going to wait for all the things that will happen in "One Piece," if he will be able to join the straw hat pirates or if he will just end up as an alliance with them. Lets wait and find out.
