Originally Posted by whitetiprs
well I know that they are predators but I do not think that they move off the sand bed. so they might be good as sand stiffters.
Olives (Oliva sayana
in this case) are predatory within the sandbed. They will primarily consume other gastropods (bivalves mostly) and worms I believe. Once done, they usually die. They are of no benefit to the tank.
what about conchs? are they good?
Much better choice but you'll find nassarius are also a good choice.