But frozen piece of fish or clam or what ever, is not the same as food in the ocean. I think that fresh sea food freeze dry and use to formulate dry food is likely better at retaining the nutrient, and with a lot more variety than a few piece of fish that we can get. Good dry food are from the sea, preserved by drying them. I think a good dry food have a much more diverse source than the few species of frozen food we can get for our tank, even if we use human's food.
Omega One, and Otohime are the two food that are really good. All I can said is that feeding my fish with these food, I can compare them to anybody's fish and will not come out second.