As you have learned, if you want to keep any kind of walking critter, you need a tight fitting lid, with no cracks or crevices they can squeeze or pry their way thru, not only crayfish, but shrimp, crabs whatever. If they can fit, they will craw into overflow pipes, tubes of any kind, and if its not heavy enough, they are strong enough to lift quite a bit more than their own weight.
