They were never reef safe in the first place but with caution, they will nip on on corals if not well fed. And really have to make sure they ARE well fed. I kept them for 3 months already. I did notice they were plucking and nipping on the zoas at first. So I tried feeding my fishes more often and the shrimps stopped and start eating whatever food that drops around them. And hasn't been any problems so far, planning to add more of them