Was Arlong in imprissioned in impell down?
The concensus was that Fishmen should be taken somewhere else because if they managed to slip into the bluegori's food gathering vents they'll be as good as free, but what we saw was too Impel Down-ish, Except for the clouds.
Isn't the calm belts open seas supposed to be "Absolutely calm"? Well ID counts as an island because it has a Eternal Pose, so it should have weather.
The point is: Arlong was sent to ID once, why wasn't he taken there? Or why didn't he showed himself during the escape?
Unless he was on Lvl six in a "Two strikes and you are erased from history" rule, he should have been around lvl 3 or 4, and part of the breakout league, and jumped water once they reached the door.
The development that Arlong was once In Impel Down makes think that he might be back in Fishman Island.
About Otohime.
She has color of Observation and yet she is marked as "Assessinated".
Luffy has been able to sense even Vanderdecken's attacks.
She's been shown to be nimble enough to dodge bullets.
My guess is that.. she is going to chose to sacrifice her life.