Fish McBites are cooked in the same fryer vat as the Filet-O-Fish patty, which contains a small amount of whey (milk in the breading.

Big Macs and Chicken McNuggets have worked for McDonald's over the years, but its new Fish McBites look to be a non-starter.

Big Macs and Chicken McNuggets have worked for McDonald's over the years, but its new Fish McBites look to be a non-starter.