IME Elegance, Frogspawn & Torch can grow at a good clip without target feeding. But if you're feeding other creatures oyster eggs or ither plankton-like food, I'm sure they'll utilize it. If you're trying to boost growth they can also eat small mysis shrimp. I've watched closely when feeding my fish cyclopseeze which is easy to see because it's bright red, and it seems the long tentacles are well adapted to snagging food from the water column even when not target fed, unlike some other corals.