Ha, I know what you mean.
It's entirely possible that the crab survived the trip just fine, I've seen small mysis shrimp and copepods get sucked and spat out, the in-and-out is so fast they don't really have a chance to get too pummelled (I think it's when the object is bigger and gets jammed in there that the blades are doing a chop-chop-chop number, but if they fit in between the blades they might not even be touched).
But OTOH, it's a crab. Crab on beach = "tee hee a crab!". Crab in tank = "ah @^%$^%!$ stupid crab". Well, usually anyhow.
