there is a possibility that they will, but they usually prefer not to because serpent stars do not act like regular sea stars in that when the shrimp is feeding on them they do not stop moving. So while they can, they usually go after other sea stars. They will eat the small asterina sea stars and I would imagine that eventually they would rid your tank of them, but the shrimp are known for making the sea stars last awhile, and those sea stars are known for their ability to regenerate and multiply really quickly so it might take a bit of time for them to eat them all.