I have a 4-inch fighting conch in a 75gallon. I know conchs hide for days, but I have 3 other small Tiger conchs that are always out and about. This guy, hasn't showed up for months. But when he does he usually knocks all the frags and small rock above him. I used a stick to scout the sand in open areas but couldn't find him. Is it possible conchs got stuck under the rock and died?