I used to feed my anemones silversides but I have since stopped feeding that food altogether. Just too many horror stories about people losing anemones that they've had for years and years because of a "bad silverside". It seems as if that if the food can rot or decompose faster than it can be digested by the anemone, you run the risk of a bacterial infection taking down the anemone altogether.
BTA's in particular, are really not very sticky to be effective predators. Feeder fish can probably be eaten easily by the BTA because .. well, they're going to die anyways. But most healthy SW fish are going to evade capture by a BTA for example. They're just not sticky enough.
I noticed though, that some foods do elicit (illicit? Hmm no that's not right
) a more vigourous feeding response than others. With BTA's, this was always a shrimp, or shrimp-like food (eg. cut up prawn, or popcorn shrimp, or mysis, or krill .. etc. etc.), over other things like shellfish (oysters, mussels, clams, scallops .. in fact scallops usually got spit up anytime I tried to feed it .. they wouldn't even eat the stuff), and even cut up pieces of fish filet. So that told me that at least these BTA's I was keeping were just not all that "interested" (for lack of a better word) in heavier foods.
Anyhow just some more random ramblings.