User blog comment:Monkey.D.Me/Is the next crewmate of Strawhat will be a Mermaid???/@comment-3060121-20101219025614

I doubt it will be a mermaid. If it is a merfolk/merperson it will probably be a merman. One who is over thirty so that he can walk on land. Maybe he will be against the new fishmen(if they are antagonist) then help luffy then become a member.