Clam Parasites

[KT & SJ]

Aside from pyramid snails, certain fish, shrimp or crabs, what other parasites/predators can a clam come in contact with in a reef system. I picked off a very small "bug" that I found on my clam and threw it under the microscope. It looks like a tiny semi-flattened pill bug like critter and was on the underside of my clam. The clam is in the sand with a shell that it has attached itself to. I brought it up to the top of the tank to get rid of an aiptasia that had taken up residence on its shell. I gave the clam a once over and noticed several of these little inverts crawling around on its underside. Harmless DSB critters? I hope.
Thanks for any info,
Shauna