Overcooking will toughen their flesh. Make sure you don't overcook fish. Combine olive oil, lemon juice and wine or cider vinegar and herbs. Turn fish once if using a barbecue. There is no need to turn fish if using a foil-lined griller.
Fish is cooked when the flesh is white and flakes easily when pierced with a fork.
Do not overcook fish or it will be dry. While fish is cooking, heat marinade in a small saucepan, adding lemon rind. When fish steaks are done, place on serving plates and pour over hot marinade mixture. Grind pepper over fish and sprinkle with a few pieces of rock salt, if desired. Serve with vegetables, salad and crusty bread.