Lay the fish on a flat work surface and hold it by the tail with one hand. Gripping a knife with your other hand, scrape the scales off the fish starting working from the tail towards the head. Once the fish is perfectly descaled, rinse it under cold running water.
Using a sharp knife, make a deep cup in the fish from the head to the middle of the belly. Carefully remove the guts.
Insert an index finger inside a gill and pull strongly to extract it completely. Then wash the fish under cold running water, both inside and out.
Put the fish onto a plate, season with salt and pepper, place half a clove of garlic inside the stomach cavity. Then, drizzle and cover with extra virgin olive oil.
Preheat a grill and brush with live oil. Once hot, place the fish on top, flipping it only once using two spatulas, halfway through cooking.
Cooking times will vary based on the size of the fish.
Consider that when working with a well-greased grill, the side of the fish in contact with the grill should not stick when it is done cooked.