User blog comment:Woohoot/The potential of Fishmen/@comment-25926617-20150708164103

I think #5 is the best reason because of most of the fishmen that we have met they are kinda smug about it and they expect to be better no matter what. Then there are ones like Jinbei who has worked hard knowing there are stronger people and he has gotten pretty strong himself but most fishmen stay on Fishmen island thinking they are better than everyone but the ones that leave i.e. Tiger, Jibei and the sun pirates all become strong. The only exception would be Arlong but the reason he stuck with that is because he hated humans for 'killing' his captain.