Zoas are very hard to feed, unless they are a Palythoa type zoanthid, which are usually large.
The problem with feeding zoas is they need to be target fed. The small zoanthid type do not accept food to easily. They usually close up if the food particle is too big, or a fish/critter comes along and eats the food.
The best way I have used is to feed right before the lights go out. Maybe 15/25 minutes prior to lights out.
Take a small pipette (plastic) and some food. Small size is good and frozen enriched brine is probably best.
Turn off all the pumps in your tank and get ready for some backache.
Melt the Brine cube or chunk in a cup with tank water and suck some up in the pipette. Then carefully squeeze some of the food onto the oral disk of the coral. You'll have to hang by the coral just to make sure it accepts the food and closes on it. Otherwise your fish will eat it.
After you've fed most of the coral, turn off the lights. Wait another 15 minutes before turning the pumps back on, otherwise the food will get blown out of the corals mouth.
You can do this once or twice a week. Anymore then that and you might experience an algae bloom from overfeeding.
That's it.
