Brom Passed Away (we think)

We came back from vacation to find the new black snail for Lowden's aquarium, Brom, was not in his shell anymore. We think he just passed away. Or maybe the fish ate him. Or really...who knows? I hope he didn't crawl away or something. (bleck) Honestly, we are not sure. It is a bit of a mystery. But, Lowden was very upset as he doesn't like "when my animals get sick or die".