So, I'm thinking one of these could be good tank maintenance.. as my tank is already getting crowded with pond snails and ramshorn snails.. and I just got a batch of MTS so I was thinking one of these guys would be an awesome addition, however, I don't want to kill off ALL my snails, as I enjoy them being there.. and I actually have gotten the last bunch on purpose, but how's this guy work? Does he just eat til they're dead? eat only for food or fun too? How about with nerites and briggs? I don't want him to eat them! Help! =)