Many arguement prevails on whether or not to feed zooanthids. I have personally witnessed systems which thrive without adding any food at all. Zooanthids are photosynthetic and they will fair perfectly well without food additives. Feeding is a secondary, not primary source of sustaining nutrients for zooanthids. If a colony doesn't exhibit a prey/capture behavior, it doesn't necessarily mean that it isn't feeding. I feed very lightly every 3 to 4 days a mixture of DT's Oyster Eggs, ESV's Spray Dried Marine Phyto Plankton, Phyto Feast, Frozen Cyclop eeez and periodic brine or mysis.
Zoos and Palys will even feed at night time, this is why one of the feedings is done 2 hours after the actinics are off with my moon lights on. I turn all of the circulatory pumps off and I allow the food to suspend and slowly settle. I will turn the pumps back on for a few seconds just to stir any food near the surface.
A system with stable parameters across the board, with adequate lighting and most importantly, a very strong but not overpowering random or oscillating current, will keep your zoos very happy and healthy. I have found that zoos are very forgiving in that stability is more important than perfect parameters across the board with the exception of Alk. A dkh of 9 to 10 is optimal.
Bottom line, a water change at least once a month to replentish trace elements, strong current, good lighting and stable readings will yield a very good crop of zoos. It's worked for me for many years.
Sorry, didn't mean to sound like I was preaching to the choir.
Mucho
