LexX said:

I think they first wanted the flipper, then decided it looked too weird/impossible to hold a gun. Then they decided to change the hand but didn't notice that you could see the original flipper before the fight.

So they take a fish guy and hope you don't notice that he doesn't have furry clawed arms? It just does not compute.

The EU explanation is interesting/dumb. Apparently some Aqualish, from a planet covered with water, evolved to have furry five-fingered arms instead of flippers. Then they had to add another race when the Aqualish in the prequels have THREE fingers and FOUR eyes!