Preheat grill for medium-high heat, or 375 degrees F. Use a mild smoke producing wood or wood pellets for this recipe (alder, apple, etc.)
To prepare butter sauce: combine butter, lemon juice, garlic and parsley in a small saucepan over medium-low heat. Remove from heat once the butter has melted; about 1-2 minutes on the stove top. Set aside 1/4 cup of butter sauce for basting.
Blot fish dry with paper towels. Brush with a little olive oil. Combine sea salt, onion powder, paprika, pepper, and salt in a small bowl. Season well, and get the sides too.
Place fish on a well oiled grate and cook for 7 minutes. Brush with reserved butter sauce, flip (unless using a plank), close lid and cook for another 7 minutes until sea bass reaches an internal temperature of 140-45 degrees F.
Remove fish from grill, plate, and drizzle with remaining butter sauce before serving. Garnish with chopped diced tomatoes or your favorite fresh herb.