Hmm... when I put less of a bias on my other post I actually have to partly agree with Nonstophoops... for one, most people don't feed more then once or twice a day, even though all fish besides the big preds feed almost all the time all day. Second, he is right as most people are have frags... not large healthy colonies... though I was very specific about that part so you cant fault me haha. Secondly I forget that most systems house fish in much smaller spaces then they are used to in the wild, yes you can keep a pygmy angel in a 30gal, but if you want it to be safer with your corals you need a bigger tank, with more corals lol. More grazing space means less over all damage to individual colonies. I also forget, that most systems do not have vast quanities of live food in them at all times. As in the past mine had everything from brineshrimp, to copepods, to amphipods, to shrimp (mysid and similar), to colonies of algea ("edible" macros) at all times. I've found with diversity like this it helps reduce how much my omivors and carnivors pick at my corals or other fish between feedings. That said I understand why most people don't, as it takes either alot of effort to culture and dose these on a regular basis, or alot of money to buy on a regular basis.
I should have been more specific about the eating habits, I ment omivorus pygmy angels (or dwarf what ever you preffer name wise) do not usually consume corals as part of their diets. The two you reffer to from your experiences are not pygmy, they are full on angels haha which is a different story. So I did a little more research into it and pygmy angels generally consume mostly algea in the wild, wile also picking up the occational zooplankter (singular for zooplankton for those who don't know) or other similar meaty items, though sponges may be a food item as well (nothing mentioned about other corals just sponges). Where as large angels, like emperor and the like, are known to regularily consume sponges, encrusting organisms, algea, tunicates (sorta fall into the sponge catagory), hydroids (related to jellyfish and corals), bryozoans (relative of corals), as well as assorted zooplankton and shrimp and the like.
So in IMO I wouldn't have a problem adding pygmy angels into a system, assuming regular feedings and with nori sheets available in the tank at all times (prefferably in multiple locations). As for large angels like emperors, I would only add them to very mature systems, with large healthy colonies, and even then would keep a close eye on them for a wile to make sure no coral in peticular was taking the brunt of its nibbling.
