I have had my tank up for about 3-4 months. I just added my first clam today. I have noticed (before the clam was added) some small snails on my glass. They're about 1-2 mm and seem to be feeding on algae. Is there a chance that these could be pyramid snails (i.e. can pyramid snails live without a clam in the tank)? I currently have nassarius, cerith, turbo and astrea snails in the tank. The snails in question have a cerith or nassarius type shell. I have seen my nassarius snails mating, but no others. I can't find any pictures of pyramid snails, so I don't know what they look like.