I've been feeding the raw (headless) shrimp to my anemones for a few days now, per LFS guy's advice. One of my anemones loves it, and instantly wraps around food and swallows it. The BTA that's hosted by a Tom clown seems to have no interest in eating. Actually, the Tom will grab the hunk of shrimp and toss it out of the anemone. I have seen the Tom 'feeding' the anenome bits of brine shrimp, but it's impossible to tell if it's eating enough, or at all.
I leave the shell and legs on the shrimp, and cut it into pieces about the size of my pinky fingernail. Maybe the experts could advise whether that's right or not.