I believe that many of the fast fish places used to use, primarily, Cod Fish from the North Atlantic. I also appreciate it when I have the selection to choose Groper or Flounder or even Haddock however anymore I think Pollock is about all you are given the chance to get for cost of the others are prohibitive. There is another relatively "cheap" fish with a simple name (maybe hokie) that is also being used a lot. I also believe that the Pollock, as in the McDonald's Fish sandwiches, actually come from one or two fishing vessels that fish the Alaskan waters and not only do they catch their fill in huge nets but on the vessel they have complete operations that cut and process the fish not wasting any part of the fish and also includes packaging of the processed fish leaving only the unloading of the boxes and cartons when the ship finally does dock. I can't remember the names of the vessels but I did see a program which highlighted them on either Discover, Science, or National Geographic channels.