Basically, I have 3 Trochus Snails I think. I brought them yesterday and 2 of them are sitting above the water line and climbing into the filtration in the back (I have an aqua one 40 marine conversion). And then the other one is on the glass and keeps falling off and not turning its self back over. I have a semi-big blue leg hermit crab that keeps picking on it. In the past, I had 2 Trochus Snails what was eaten by the hermit crabs and now all of my hermit crabs have new shells. Is this normal behavior? thanks in advance