Creole seasoning gives the fish in this New Orleans sandwich a zesty kick, and because the fish is broiled instead of fried, it's a lighter option than what you might find in a restaurant.
Heat broiler, with rack in second highest position. Place a broilerproof wire rack in a rimmed baking sheet. Arrange fish on rack and sprinkle evenly with Creole seasoning. Broil until fish is opaque throughout and seasoning is deep golden and crisp at edges, about 12 minutes. Remove fish from oven and toast bread under broiler, about 2 minutes. Layer fillets on bottom halves of bread and top with lettuce, pickles, and tomato. Spread 2 tablespoons tartar sauce on top halves of bread, and sandwich sides together.