hello I have a 72g bowfront tank and am starting to notice ufo snails that live in the sand untill it gets dark then they come out all over the tank they are very small and hate the light. after it has been dark for awhile they come out all over the place and they seem to be eating all the empty shells on the bottom of the tank, and as soon as I turn on the lights they all fall off the rocks and bury themselves in the sand. What are they and are they good.
Thanks for the help.
Thanks for the help.