chich0.
I saw your other thread that you heard the tell tale clicking sound.
It is possible that it is not a mantis but rather a pistol shrimp. The only way to tell for sure is to see them and Pistols like to hide.
Here is a link to a site that BeelzeBOB posted earlier on this thread
Introduction to the Stomatopoda
Basically there are two types of Mantis, depending on the functionality of their raptorial appendage. Smashers and Spearers. Smashers can break open snail and hermit shells. Spearers can spear small fish that get too close.
I have 2 smashers in my display and one in my sump. The one in my sump I plan on taking to my LFS but I am going to keep the other two. They may take out a snail or crab and that is okay. I don't have any fish yet but I will and they will be safe. I do feed my mantis fresh shrimp and calamari by hand 9 okay really by chop stick) in the hopes that if I feed them well they will not bother my CUC too much.