To prepare the fish, first coat the fish with flour, tap off excess and then dip into the egg wash. Mix the breadcrumbs, coconut and walnuts together in a third pan. Finish the fish in the coconut breading mixture. Ensure that the breading is evenly covering the fish, and then repeat with the remaining fish.
Heat the oil in a large, heavy-duty pot or deep-fryer to 350 degrees F. Once the fish has been breaded, drop the breaded fish into the oil and cook until golden brown, about 90 seconds. Flip the fish once during the cooking process. Once cooked, remove and allow to rest on paper towels to absorb excess oil.
During resting, sprinkle with salt and pepper, and then squeeze the lemon over the cooked fish. Serve.