I feed my CCB in my 420 g tank by drop a frozen steamer clam in the tank one a day. As the clam thaw out, the CBB move in and start eatting, one he has his fill, and as the clam shell split open more, the rest of the fish move in and finish the clam. I have to remove the clam shell out of my tank often because I don't like the look of a lot of shell on the sand bed.
Of course the CBB also clean out all my feather duster, and a lot of my Medusa worms and other sand bed and worms on the rock. I did not have any aptasia problem so I did not know if he eat aptasia or not.
Anybody here keep more than one CBB in a reef. The books said that we should keep
one or else a pair or group.