Thanks guys for replies. Now my emperor loves this stuff if i just feed him nori as the first food for a day. Him and my YT tear nori away from my hand and go nuts. I think i will keep feeding them nori in the afternoon and after couple of hours frozen food with all the goodies. Few other fish as green chromis, flame angel and few others also goes for nori but don't eat with that gusto as Angel and YT.
Also i get lots of satisfaction by hand feeding them . Try it if you haven't already.