Rinse the fillets and pat dry. Place the fillets in a glass or enamel-coated dish with 2-inch sides, and sprinkle with the lime juice. Cover with plastic wrap and refrigerate for 1 hour.

In a large heavy skillet, combine the oil and butter, and heat over medium heat. Add the garlic and sauté only until lightly brown; be careful not to burn or the dish will be bitter. Using a slotted spoon, remove the garlic and set aside; remove the pan from the heat, but hold for cooking the fish.

Remove the fish from the dish, reserving the lime juice, and pat dry with a paper towel. Dust it lightly with the flour and shake off the excess.

Warm the skillet over medium-high heat, and quickly fry the fish for 2 to 3 minutes per side, or until brown and crisp outside and just done on the inside. Remove the fish to a heated platter and keep warm while you finish the dish.

Return the garlic to the skillet to reheat. Stir in the reserved lime juice, cilantro, and salt and pepper to taste. Heat just until the cilantro begins to wilt.

Pour the sauce over the fish and serve immediately