What are these??

[cmdw4587]

I seem to have had a sudden outburst of these little guys. The are a snail of some sort but not sure which one and if they are good or bad. Any advice?

 

[Crystal A]

Do they have little pointy noses and stay in the sand most of the time?

 

[cmdw4587]

They are on the glass when I see them at night. They look somewhat like a conch to me. At the thick end of the shell they have a ring of pointy teeth like structures on the shell.

 

[cmdw4587]

Here are some better pics of the guys in my tank.