Marinate the fish with all the ingredients, except for Butter. Leave the fish to marinate for at least 2 hours or more. Grill in Rotisserie for 30 minutes and baste with the butter each time.
If you are using a pan, Grill both sides on medium heat for 10 minutes each side, basting with oil/butter. Make sure you turn the fish every 2-3 minutes to ensure even cooking on both sides.