White shrimps are killing crabs in my tank!!!!

Hi everyone, just a question

I added 5 small crabs to my tank as a cleanup crew. I saw them missing and some empty shells. The other day i saw a shrimp playing with one and i didnt bother but today i saw the shrimp actually taking the crab out and eating it!!!!!



I have no small crab anymore! Does white shrimps attack others??! I was worried about the crabs eating my snail but i didnt know they wont make it