Hi,
I will never recommend it to one of my customers just to be on the safe side. However, in our private tank my wife and I keep several large (10" +) and smaller clams, Deresa's, Squamosa's, Maxima's and Crocea's and even a Giga's and a small Hippopus together with a Emperor Angel, A pair of Swallowtail Angels and a Golden Angel as well as a Yellow Eyed Kole Tang.
So far no real problems. On occasions I have seen the Golden Angel nip at a clam mantel but he has never taken a bite out of it. The clams fully expand and show good coloration and growth and no signs of stress.
We did have bad luck keeping any kind of leather and Xenia in this tank with it's current inhabitants. So right now it's a SPS/clam tank with only 3 large LPS corals.