The flesh will easily slip away from the bone on an aged fish. Whole fish is the easiest way to detect freshness. Eyes are clear, not cloudy, pink or sunken. The gills should be bright red or pink. There should be no slimy feel to the skin.
Fish is cold.
Preferably packed on ice. Never in water Pre-packaged fish is tightly wrapped and no liquid. Frozen fish is solid with no freezer burns, discoloration, or ice crystals. An average serving is 3 to 4 ounces cooked. A raw filet should be about pound per person, and a whole fish about pounds per person.