As of August 2015, the only type of fish sandwich McDonald's sells is the Filet-O-Fish. In the United States, this sandwich contains wild-caught Alaskan pollock taken from sustainable fisheries. McDonald's typically serves the fish on a white bun with American cheese and tartar sauce.
In addition to pollock, the fish patty contains wheat flour, water, modified food starch and other ingredients. The filet is cooked in canola, corn, soybean and hydrogenated soybean oil. The serving size is 5 ounces. The Filet-O-Fish has 390 calories, 15 grams of protein, 19 grams of fat, 39 grams of carbohydrates and 590 grams of sodium.