1 Combine sake, soy sauce, ginger juice and salt in a shallow baking dish. Coat the fish well with this mixture and set aside to marinate for 10 minutes. Drain, reserving marinade.
2 Heat oven to 160˚C (325°F). Place one fillet in the center of each aluminum foil square, brush with oil, and sprinkle with carrot, onion, bell pepper and remaining marinade. To seal the packet, bring the two sides of foil over fish and crimp closed. Fold up each end of the foil and place each packet on a baking sheet.
3 Bake for about 20 minutes or until fish flakes easily with a fork. Place foil packets on serving plate or carefully remove fish and vegetables from the foil, pouring any remaining juices over top. Garnish with lemon slices and serve.