Mix together the olive oil and balsamic vinegar in a small bowl. Arrange the salmon fillets in a shallow baking dish. Rub garlic onto the fillets then pour the vinegar and oil over them, turning once to coat. Season with coriander, basil and garlic salt. Set aside to marinate for 10 minutes.
Preheat the grill.
Place the salmon about 15cm from the heat source and grill for 15 minutes, turning once until browned on both sides and easily flaked with a fork. Brush occasionally with the sauce from the pan.