Larry,
Do you feed your CBB anything special? How do get them to start feeding? My tank is large so my CBB have things to eat until he start to eat the clam. I guess in smaller tanks, they see the clam and start to pick on them sooner. A friend of mine open oysters and clams for his CBB. He even feed the CBB out of his hand using shrimps and mysis shrimps.
Minh