"Dead food" is meaningless. To continue with the example I was using before, the extent a "real" piece of meat, for example, is nutritionally superior to synthetic protein, it is because the "real" meat contains other things - fats, amino acids, etc., that the synthetic product may not contain. This does not somehow make the "real" meat a better source of protein. I reiterate - protein is a macronutrient, it makes no difference with respect to hitting your daily targets whether you get it from a synthetic source or a fish. As for the other things you get from fish (i.e. omega 3s), these can also be found in other products - i.e. pill form. Again, whether you get your omega 3 from a fish or from the pill (which is usually just processed fish oil) makes no difference. The biggest difference is actually that the processed version tends to be much more efficient - it takes a lot more beef to get the protein you get in a 25 gram scoop of whey isolate, and a lot of fish to get the omega 3 intake you get from one of those little gelcaps.
The word "synthetic" has a negative connotation where "organic" has a positive connotation, and those connotations do not actually reflect reality. I hear people say shit like "you need to get X grams of protein in your diet each day and make sure half is from real meat" and it makes no sense. If you want X grams of protein get it wherever, and if you want the other nutrients meat provides, either go ahead and eat the real meat or again, get it wherever.
I mean personally I get about 100 grams of protein from whey each day and eat on average 3 medium sized chicken breasts for lunch and usually another piece of pork or beef on top of that in the evening, but that's because I happen to like chicken, pork and beef.