So I decided to add a couple Nerites to each tank. I picked up 4 pretty little guys this evening. While picking them out I thought I was getting 4 Tigers but once she put them in the bag one looked like a Zebra. When I flipped it over I could see a very distinct line in the shell where it turned from zebra to tiger markings! Is this common? Could it change back to zebra at some point in the future? Either way he's cool looking. I'll add a pic as soon as I lay my baby down.