I think of the beach as a big empty outdoor photo studio where you can do whatever your imagination wants. You could bring a reflector if you need additional light and it's not windy.
Perhaps your photo is poor because it's weak in lines, composition, areas of light and dark. The Edward Weston photo linked had all that in a big way. Perhaps you need some shapes like putting the fish on a round dark plate that contrasts with the fish and sand, or set the fish on a dark rock or a bowie knife or someone's cleavage or tired worn hands. Wet the sand to make it dark.