What's killing my peppermints?!

[oceanhighz]

well, here's the story, I had two peppermints, a cleaner, 2 serpent stars, 1 emerald crab, 1 sally lightfoot, a bunch of little hermits, a true perc clown, and an algae blenny. all of these things have never caused a problem and I haven't lost anything until between 1-2 weeks ago. Then I when I woke up one morning, I only saw one peppermint shrimp, no remnance of the other. I searched and searched some more and never found a thing. Then yesterday when I came home from school, I looked in my tank, and found my other peppermint completely missing it's head and tail. I don't know what is doing this, I have pondered this since it happened, my only idea would be a mantis shrimp, but I have heard no popping noises whatsoever, and don't seem to be missing any hermits. Now mind you, these were fairly large peppermints, so this is my only idea, anyone have any others? I bought a mantis trap today, and put it in with a piece of shrimp inside, we'll see what happens, I'd still like to know what you peopel think. Thanks.

Brandon

[Pomacanthus1]

Unless you catch or hear a mantis, i would suspect the serpent stars or the sally lightfoots. Serpents (especially greens) are known for catching and eating small fish and inverts, and the bigger sally lightfoots get, the more aggressive they are.