that clam is a crocea and the other is a maxima. crocea are known to hold their incurrent siphon open more than other clams, they both look ok. though i would like to see a top down pic of the maxima, specifically the area of the mantle that is retracted.
what fish / inverts do you have?
both those clams wouldn't like to be up on the rocks, closer to the lights, though they may do fine where they are ( 250W halides ). these two species are the most light loving of the tridacnid clams, generally clams move in search of greener pastures, he is probably asking for more light.