hmm, i have some of these little snails, too. i lost a few maximas over the last 2 months. looked like the pic, although i suspect it was that disease others have been battling. i still have 1 crocea and 1 derasa. i have seen some snails hiding in the upper scutes (flutes?) of the crocea. unfortuneately, it is firmly attached to a big rock. while not IMPOSSIBLE, it is a chore to remove the rock to pick off the snails. what do you think i should do?
the derasa can be lifted from the sand. i have found snails under this guy, hiding in the sand. i have also found little bristle worms under here, too. usually when i move the derasa, my spotted hawk comes over to snack on the worms. i suspect he also picks on the smaller snails.
i don't think i can put in a 6-line, since the hawk already does battle with the pseudochromis. i often remove the little snails hiding under astreas.