CHOOSE YOUR FISH
The French like to see their fish with the head on and the gills intact. This can be disconcerting: some fish, like loup (wolf-fish) are intimidatingly toothy, and monkfish are breathtakingly ugly. But looking a fish in the eye is the best way to judge its freshness. A fish with dull, sunken eyes and a generally hung-over look is past its prime.
Look for feathery, coral-pink gills (fold the gill-covers back for a closer look) and avoid fish with grey and slimy gills. If the fishmonger will let you, give your prospective purchase a poke. The flesh should be firm and your finger shouldn’t leave a dent.
Finally, trust your nose; a really fresh fish should have very little smell. As for crabs, lobster, prawns, oysters and other shellfish: harden your heart and buy them alive and twitching.