Member-only story
Gastro-nomics
The Real Reason Every Chain Is Suddenly Introducing a Fish Sandwich
From the McDonald’s Filet-O-Fish to the new Popeyes Cajun Flounder, the battle of the fish has become a spring tradition

Gastro-nomics is a new column about the intersection of food, business, and culture.
Around this time each year, drugstores lay their pastel eggs, Peeps appear in bins for impulse buys, and enormous hams take center stage in deli cases across America. If Easter-themed products are a neon-colored commercial iceberg, there’s also a lesser-seen segment swimming below the surface. I’m talking about fish sandwiches.
Typically, in the late-winter weeks following the Super Bowl, restaurant chains around the United States begin to unveil their seasonal fish offerings. And this year was no exception, with new sandwiches from several big chains, including Popeyes and Wendy’s. This annual fish parade happens without much explanation or context, in the way that most normal promotions begin. But the history of fish sandwich season has a complexity and durability that reaches far beyond, say, the great Ghost Pepper trend of 2015.
McDonald’s now sells roughly 300 million Filet-O-Fish sandwiches a year, a quarter of them during Lent.
The story begins back in the 1960s when a McDonald’s franchisee in Cincinnati named Lou Groen faced a pressing dilemma. Each week, his heavily Catholic consumer base would customarily abstain from eating meat on Fridays, leaving him with little foot traffic one day a week and jeopardizing his business. To find an alternative that would keep his store afloat, Groen took inspiration from a fish sandwich at a nearby restaurant and created his own battered version with tartar sauce.
But before he could introduce the item, he had to get permission from McDonald’s chief Ray Kroc, a man known for his…