That's a really nice tank rich...Hopefully you can get it out without dismantling everyhing and stressing out those tangs....Try to get a 20oz sprite bottle and tie a string around the top of it...Put a piece of shrimp inside the bottle, put it on the bottom of the tank after the lights go out, and wait for the mantis to go in there...when he does, yank the bottle out of the tank..Hope this helps...Let us know how it goes