Lucky you Anemones will decide what they like to eat. Some like fresh market shrimp, some like silversides (bought at fish stores), while others may like mysis shrimp, etc. You should do some trial and error to find out which your anemone consumes and which it spits back out. Make sure your RBTA receives good light. Light energy (especially if you have it hosting a clownfish) may be all it needs to sustain itself without special feeding.