I think you would be hard pressed to show that the worm was an amphinomid and that the tissue was healthy. If you did, it would contradict years of research on these worms, and you would have some pretty groundbreaking research on your hands.
They can only change as much as physiology allows. Being in captivity doesn't change how they find food, which is by smell. If you were stripped of your senses except for smell and a much simpler sense of touch, I could let you loose in an apple orchard and you would starve to death surrounded by potential food just because you have no way of knowing it's there. It works the same way with fireworms. Decomposing animals give off characteristic compounds that these worms respond to. If those compounds aren't there the worms don't respond and don't eat.
Polychaete translates to many bristles. It covers all bristleworms. The hobby didn't invent the term bristleworm.
No doubt there are some polychaetes that will go after healthy clams, but those will go after clams regardless of what size and none of them are fireworms. There are lots of things wrong with a statement like that. Chief among them is how in the world would he know that the clam was healthy? People assume you can look at animals and judge whether or not they are healthy, which isn't true in probably the majority of cases. There is no way to look at a clam externally and tell that it's healthy. They only make it clear sometimes that they are unhealthy before they die. Since he only thinks that the worms attack clams under 3'' that would suggest to me that the clams are starving to death. Under 3'' they don't make enough food from photosynthesis alone, and there is no outward sign that they are starving.
