I added a relatively Large Damsel about 3 weeks ago to my tank which already had 2 smaller damsels and 2 Clownfish... and all of a sudden the Large damsel went missing. There's no way it could have jumped out or gotten sucked up my filter, it's just way to large, and I checked all around the tank....It's like this Damsel discovered the ability to teleport.\n \nI have also had a number of relatively large Snails be killed off. I have a Cleaner Shrimp, big Halloween Hermit Crab, and an emerald crab. Could any of these guys be killing my snails or the Damsel too? I looked at the marine compatibility chart and they all seemed to get along but with my Damsel gone and my Snails dying off, there's a killer in the tank and I am having trouble identifying it.