I recently got a 1" navy blue mantis shrimp from another hobbyist. I put it in one of those plasic critter keepers and placed it in my sump for the time being until the 5 gal tank for him finished its cycle. Well anyway it somehow managed to squeaze out of the critter keeper get into my sump, crawl into my main pump, avoid being minced by the impeler, went up the return pipes and into my reef. what do you all use to catch such a small mantis?