Grilled fish is probably one of the healthiest dishes that exist. It's low in fat, gluten free, etc., perfect for those who are dieting and for everyone who loves eating delicious and wholesome foods.
Remember that sea bass, like any other fish, is delicate, and should be cooked quickly to avoid overcooking. If you like, you can marinate the fillets in a bit of lemon juice and olive oil, but only for a few minutes, because you're not making ceviche, you're just flavoring fish.
When you add barbecue sauce to fish fillets, you should avoid any sauce that is too intense and will overpower the natural flavors of the fish. Remember that fish is the star here, so the sauce should be flavorful and intense but not overwhelming.