I've had a cleaner shrimp in my tank and added a red serpent seastar and an arrow crab to my tank the other day. The next day the cleaner shrimp was dead. At first I thought it was the serpent because the shrimp was tangled with the serpent and the arrow crab was also eating the shrimp. I was told by my lfs that the serpents are peaceful and that the arrow crab was the culprit so I returned the arrow and got another cleaner shrimp. Well, I put the cleaner shrimp in my tank and he is gone. I think that the serpent was the original culprit. Is this possible? Has anyone had any experience with this? There is nothing else in the tank that would have done this as the original cleaner shrimp was in my tank for a month or so and was completely healthy. Thanks and I appreciate the feedback.