Wash the fish thoroughly under cold water, making sure to remove any remaining scales or guts.

Dry the fish completely inside and out with paper towels. This step is important for even cooking and a crispy skin.

In a small bowl, mix the lemon juice, minced garlic, olive oil, oregano, salt, and black pepper. Stir well until combined.

Place the fish in a large dish and pour the marinade over it. Make sure the fish is well coated inside and out, and that the marinade gets into the cuts.

Cover the dish and refrigerate for 30 minutes to 1 hour.

Light the charcoal in your grill and let it burn until the coals are glowing and covered with a light layer of white ash.

Brush the grill grate well with a little oil to prevent the fish from sticking.

Carefully place the marinated fish on the hot grill. Grill each side for 5-10 minutes, depending on the thickness of the fish and the heat of the coals. The fish should be golden and crispy on the outside, and the flesh should be opaque and flaky on the inside.

Once the fish is cooked, carefully remove it from the grill and transfer it to a serving platter. Garnish with chopped parsley and extra lemon slices.

Serve the grilled fish immediately with grilled vegetables, a fresh Greek salad, or boiled white rice for a complete, healthy meal.