I still remember the bass. I had it last year, at a restaurant in the southwestern corner of Spain. It was brutally overcooked, feeling to the touch of my fork like a tensed bicep, but it was nonetheless the most delicious fish I'd ever had. Little wonder, given its pedigree. If the typical fish farm resembles a floating feedlot, releasing pollutants into the ocean, Veta la Palma—a fish farm not far from that restaurant—is something closer to a water purification plant. Water from the Guadalquivir River is pumped into the farm's 28,000-acre network of canals, and when it's pumped back out, the water is actually cleaner. Sea bass, mullet, eels, shrimp, and sole—all of which feast on what the ecology naturally provides—are sweet and pure. Rod Mitchell of Browne Trading Company, a man who knows fish like no one else, imports it weekly to some of the States' best restaurants. "Only the most pristine fishery could produce fish like this," he says. —Dan Barber, Blue Hill restaurants, New York City