Yep RedSonja, you're feeding perfect food. There is a pack you can get at most grocery stores thats a mixture of clam, shrimp, scallop, etc. that is uncooked and frozen. That's really good for them.
I've noticed in the 3 years that I've had my BTA that the bigger food that you feed, the more time they shrink down and purge food and excrement. The smaller it is, they hardly ever do that.
I feed chopped up shrimp and Rods Food and baste it into the anemone. Anything that gets out the fish and shrimp take care of.