Must be a very different variety than the ones we have here. These are meat eating machines. When I was a kid, I kept one in a gold fish bowl at the head of the stairs between our lower level kitchen and upper level livingroom. So, those stairs were always being used. That crayfish would hear our feet on the stairs, and he'd climb up to the upper level in his bowl, so that he had his claws sticking up out of the water, hoping for a tidbit of hamburg.Well cool!
I rember them sifting through the gravel and moving it about, they're wisker like mouths sucking stuff up, sort of shovleing debris in... Defiantly filter feeding...
Re: starting corn inside: When I've done it in the past, I used newspaper pots. I've given up the practice, b/c it hasn't seemed to grow as well when started inside. However, I always pre-sprout corn and all the rest of my large garden seeds.