Saw one in my tank last week swam up the front of the glass and settled on a big mushroom in front of me . typed in mantis shrimp on google and the first picture to come up was him.hes a quilla mantis ,a spear-er and pretty bad news for me and my fish if he grows up. tried to find some more information about him and was assured by my local fish store that it is very unlikely that he would survive to reach a size that would make him dangerous to me or my fish if my fish do start showing any signs of distress I'm afraid I am going to have to dismantle my reef and check every hole in the live rock and get him out of there carefully (nightmare You have seen the tank) Then he is destined for my sump. Grandad.