I think it is a grey area. Some people swear that their fish feed their anemones; some people swear that they don't, some people think that the fish are bringing the food to their "home" so that they can eat in peace (and then the food ends up in the anemone, so it "looks" like the fish fed the anemone, but it was accidental).
My ocellaris have never fed their hosting anemones in four odd years of me observing them. I could just have stupid fish though, I have no idea.
My own take on this is a bit wishy-washy. I decided that I cannot rely on my fish to feed "their" anemones, but I've noticed that as long as I feed the tanks well enough the anemones are usually more than capable of taking adequate care of themselves by catching the food as it flies by.