ARROW CRABS DONT WORK! They eat bristle worms not aiptasia. My bad, I remembered it wrong because I started noticing aiptasia and bristle worms about the same time. To get rid of the aiptasia, I bought peppermint shrimp and joes juice. BE WARNED....there is a difference in peppermint shrimp. I think its california and indo-pacific. the cali ones dont eat them as much. sorry about any confusion