I've had a new kind of snail show up in my aquarium. This happens occasionally. At first I only saw them at night (one or two), but now they are bigger and venture out when the lights are on.
They are shaped like small abalone- all white, smaller than a dime at this point. The soft body extends well beyond the shell when they are moving.
Is it some kind of abalone common in our aquariums, or is there something else with that shape of shell? Should I be glad they are in there?