Caribe > Any Other Piranha
Small ones can't but for big ones acrylic tanks are recomended. Some people will put a acrylic sheet under their substrate though a mantis shrimp shouldn't be able to break an appropriatly sized tank. Mines in a 10g sump. For their size they do have pletny of power. Mine has hollowed out a solid rock for his burrow.You have any preventive measures on the bottom of your tank as are these not the little suckas that will pucnh a hole through the bottom??
so he's afraid of u huh?
Mine likes to roam around the tank often, maybe ur feeding him too often, have u tried hermit crabs for him to venture out and capture?