I have a 29 bio cube. Recently a bot 2 poly frags and placed them in the tank. Each moring one of them would be on the sand upside down. Finally one day it completely disappeared. I tore the tank apart looking for it. Nothing. The second larger brown polyps were doing well but now they are getting knocked or pulled off their rock. I witnessed a hermit crab pull it down yesterday. Today I saw a hermit by the polyps messing around this morning? Do snails or crabs eat polyps?