In a small bowl, mix the olive oil, lemon juice, salt, pepper, garlic powder, and paprika.
Pat the fish fillets dry with paper towels. Coat them all over with the olive oil mixture.
Heat a gas grill, an electric grill, or a stovetop grill pan to medium-high.
Place the fish on the grill. Brush their tops with any remaining marinade. Grill the fish until cooked through - about four minutes on the first side and three more minutes on the second. Lower the heat to medium if your grill becomes too hot.
Serve immediately, garnished (if desired) with lemon slices and chopped cilantro.
Video
Notes
The fish is done when its internal temperature reaches 145°F. It should have a firm, opaque flesh that easily flakes with a fork.
You can make this recipe successfully with other white fish, such as cod or halibut, as long as they are about ½-inch thick.
I typically use a stovetop grill pan that accommodates three fillets, and this recipe reflects that. If your grill has more space, you can cook more fillets and adjust the remaining ingredients accordingly.
You can keep the leftovers in the fridge, in an airtight container, for up to three days. Reheat them in the microwave covered, or flake them and use them cold as a salad topping.