The conventional wisdom says buy fish Friday through Sunday when the catch is fresh. But a conversation with three veteran fishmongers—including Mario Porcelli at Chelsea Market—reveals a hidden advantage to Monday shopping. On Monday, inventory rotation is most aggressive. Mongers are cleaning cases, discarding anything questionable from the weekend, and receiving specialty items (halibut cheeks, sea urchin, wild striped bass) that didn't move in the tourist rush. This creates opportunity. The Retailer's Secret Logic Sunday's crowds mean Monday morning restocking goes deep. You're shopping when the counter is most curated, not most full. Ask your fishmonger what they'd buy for themselves on Monday, and listen. They'll often direct you to something stellar that no one recognized over the weekend. "Monday is when I put the interesting stuff on ice," Porcelli explains. "Friday people want salmon. Monday people actually talk to me." Build a relationship with your fishmonger by shopping consistently on Monday. You'll discover regional species, better pricing on bulk purchases, and insider knowledge about what's truly fresh versus what's simply available.