i have tons of the cup corals (at least i think that's what they are called). they will open up and have clear/white tentacles. they are non photosynthetic, and will eat anything
i don't generally feed them, they just grab food particles out of the water
if those red things retract, then yea, i guess they could be molusks or filter feeders, but if they are fibrous, and layered, they are kelp stalks. i have 3 or 4 of them.