1) Make sure the fish eyes are bright white. It should not be dull or cloudy. 2) Press the body of the fish with your finger; it should be firm and elastic (bounce back). If it leaves a dent or is too soft then it is an old fish. 3) It should not have a very strong fish odor. 4) Check the gills; they should be nice and red. If it is brown or grey then it is old. 5) Shiny and moist skin is a good indicator that the fish is fresh. The skin should not be dry or have dark spots on it.