Not only that, but the chain is rolling out a new deluxe version of the sandwich ... McDonald's uses MSC-certified pollock for the venerable Filet-O-Fish, as does the rival Burger King Big ...

There's a method to the madness—and chances are, it's not what you think. We got to the bottom of this McDonald's mystery.

Alaska pollock, the fish that makes up the famous McDonald's Filet-O-Fish sandwich, is now featured as a new menu item in wraps at the fast food chain's Canada locations. For a limited time ...

Arguably one of the most controversial items on the menu, the Filet-O-Fish sees a significant spike in sales every Good Friday. 'We can confirm that each Macca's restaurant sells an average of 126 ...

Filet-O-Fish sandwich on top of the box - Robson90/Shutterstock ...

Filet-O-Fish on top of blue McDonald's box - Robson90/Shutterstock ...