Preheat the oven to 400 degrees F.

Score the fish with a paring knife by making several 1-inch slits in the skin on each side, being careful not to cut in too deep. Put the fish on a dish and drizzle with the lemon juice and 1/2 of the oil. Press the garlic into the score marks. Rub the spice mix all over the inside and outside of the fish. Cover with plastic wrap, and allow it to marinate in the fridge for one hour. Heat a skillet large enough to hold the whole fish over high heat until it is almost smoking. Carefully pour the remaining oil into the pan and let it heat. Place the fish in the pan, sear it well on both sides, and then place it in the oven for about 7 minutes, or until the fish flakes easily. Transfer the fish to a serving platter.