I was reading it as a weird turtle (robo arm as robot head) for quite a while.  There are some definite readability issues here despite the good animation.

Rid of the black line across the preview, it's not pixel art. You require both to be for this to be accepted in. (Rules are strict so we maintain pure pixels throughout this gallery)

Otherwise, really nice sprite. :)

 It almost reads as a dolphin, I had to take a long look to see that those were legs not fins.