In a large saucepan, heat the oil with the garlic over moderate heat. When the garlic sizzles, add the fish stock and wine. As soon as the liquid comes to a boil, add the clams and cover the pan. Steam the clams until all of them have opened, 3 to 5 minutes; discard any unopened clams. With a slotted spoon, remove them from the pan and place them, shells and all, on top of cooked pasta. Stir the parsley into the liquid and spoon the liquid over the clams and pasta. Season to taste with black pepper.