Emerald crab assassin?

[Esreef]

So after feeding the tank last night I noticed the emerald crab chase down, flip over and drag a pretty good sized nassarius snail toward a rock :eek1: but I intervened and freed the snail before he could get it under the rock...

Is this common for emeralds? I thought they would only eat dead/dying things and algae and it could very well be he was trying to steal food from the snail but I didn't have the heart to wait and see...

Side note, I have noticed empty shells accumulating on the sb, chalked it up as just the normal course of reef life but would be more than happy to move the crab to the sump if he is a serial snail killer... although there are snails down there too.. hmmm

 

[Sugar Magnolia]

Mithrax crabs are omnivores, so yes, when they feel like a snack is in order, a snail makes a quick, easy to catch meal.