Keithhjs
Aquarium Advice Addict
I had one hitch a ride in long time ago. Kept hearing it & finally one evening I saw a flash of movement on a piece of live rock so I reached in and yanked that rock out, smashed it with a hammer & caught the mantis shrimp. Took me like three months to get a visual on which rock he was in. You can buy a trap & go that route if you can't find where it is then hopefully you can trap it.