When I feed mine I give it mysis. I don't really target feed corals though. My Duncan does a great job at snatching up food during regular fish feedings.
Duncans have a great feeding response. I spot fed mysis until it got so big. I do broadcast reef chili twice a week. I also spot feed my torches mysis. I’m sure they get a little of everything I feed my fish.
I’m new to reefkeeping but once every 3 or so weeks I’ve been giving tinnny pieces of fish to my Duncan and they chomp it up! They’re getting nice and plump and my frag has grown 2 new heads? (If that’s what they’re called?) since September. I also do either a broadcast of roids or AF pure foodA couple times a week but may slow that down now that I have a few fish in the tank.