About 20 (maybe 25 yrs ago?)McDonald's (Golden Arches)exclusively use cod in their fish sandwiches. What changed? Cod was expensive,so they switched to a less expensive white fish.

Years ago as a freshman in college, an erstwhile freshman, who was British, always had tuna subs whenever we (the collective went out on weekends). I asked him one day, why he always orders tuna and don't they have tuna in England? He answered, Of course, but it's a lower class fish. I don't think that I'll ever forget that.