i,ve recently purchased a madarin dragonet and has been in my tank for two weeks but has disapeared over the past 3 days i,ve looked about after lights out with my torch but all his usual spots are vacant i,ve read tht they can bury themselves in the sand but would they for days i,ve also had a clown fish disapear last week and the only fish eater in my tank is my giant mushroom is this the culprit even though he is fed once a week ! ANY FEEDBACK WOULD BE GRT