i feed mine: Sally's Silversides, San Fransisco Brand. ive used them for more years than i can remember, and never had any problem, ever!
Petsmart is cheaper than any of my 5 LFS.
if its a small anemone, appx. 4"- 6", cut of the flesh (backside) and feed only the head and guts. they have the most protien and your anemone will not reject them... :thumbsup: