The first rule of buying whole fish: ask your fishmonger when it arrived. Not "Is it fresh?" but specifically: "When did this fish come in?" A reputable monger will answer immediately. Anything more than 48 hours old for most white fish, or 36 hours for delicate fish like halibut, is pushing it. Frozen-then-thawed fish is perfectly acceptable if you're cooking it the same day, but you deserve to know what you're buying. The Eyes, Gills, and Smell Test Next, look at the eyes—they should be clear and slightly bulging, not cloudy or sunken. The gills must be deep red or pink, never brown. Finally, smell. Fresh fish smells like ocean spray and salt, never ammonia or funk. If the fishmonger seems annoyed by your questions, find a different counter. The best ones will flip the fish to show you the gills without hesitation. For fillets, the same timeline applies, but transparency matters more. Ask to see the cut—the flesh should gleam, not look dull or dry. "A good fishmonger treats their counter like a sushi bar: obsessive about temperature and rotation." Don't buy pre-cut fish on Monday if the store restocks on Thursday. Build a relationship with one person at your market, and they'll alert you to the best deliveries.