BTAs will eat squid, krill, silversides, mysis, table shrimp, scallop, to name just some of the options. A couple of times per week is fine, small pieces no larger than a small peanut is preferable. Larger pieces are likely to be ingested, only to be expelled a few hours later. Some people don't target feed their anemones at all, so the only food the anemone gets is food the fish don't eat first. The majority of a BTA's nutritional needs is met through the zooxanthellae that live in their tissues.