To be quite honest, I'd say they'd eat any shrimp you put in there, unless it was liike... a giant lobster. Heh. The shrimp would eventually molt, and well... mm, dinnertime! A rare delicacy indeed.
You could try something like the Vampire shrimp which is much bigger, and provide plenty of hiding places. That would help any shrimp out greatly. Or maybe even crayfish?