Fun fact about the peacock mantis shrimp: They can punch really fast. Yeap, you read the word "punch' as in holding the fist like this ✊ to strike someone/something.
They can punch at the speed 50 times faster than the blink of our lame human eyes. Also it's been said they can punch with speed equal to a firing pistol. These guys can break into rocks and shells (for food, so.. bye clams). So don't think about putting them in your aquarium unless it's made of diamond or Adamantium.