I'm pretty sure that zoa prefer all the junk that is in the water column. I believe that they are not a coral that would achieve better growth rates if one were to target feed them, but I could be wrong. I'm gonna look it up.
ok, I found an article by Eric Borneman stating the following:
Thus, we can see that some zoanthids may enjoy feedings, some (especially certain azooxanthellate Acrozoanthus and Epizoanthus) may require food, and others may not even accept food that is offered to them...instead turning up their tentacles and stomping off in a huff at the audacity of such poor culinary choices. If a zoanthid is large and seems to rapidly consume food, one can assume that it will benefit from occasional feedings. Otherwise, they are likely getting enough from the immediate environment.
I was feeding one of our mandarin's some mysis shrimp today, and we just put another koralia in the tank so the shrimp went all over the tank, one landed on a frag of bam bams, and one polyp ate a whole mysis shrimp...i dont know if its good for it or not, but its the first time ive seen a zoa eat any whole food before. ill update this if i notice anything unusual happen to the zoa.