Preheat the oven to 450ºF. For each fillet, fold a 12 x 24 inch sheet of aluminum foil in half to make a double-thick 12-inch square. Set aside.

Rinse the fish, pat dry, and set aside. Heat the oil in a small saucepan. Add the garlic and ginger and sauté on a low heat for about one minute. Stir in the soy sauce, rice vinegar or lemon juice, and sesame oil and set the sauce aside.

Place one fourth of the carrots and water chestnuts in the center of each foil square. Drizzle on a bit of the sauce and place a fish fillet on top. Arrange the red peppers on top of each and pour the remaining sauce evenly over all. Fold each square into an airtight packet, crimp the edges shut, and place on an unoiled baking sheet.

Bake for 20 minutes, until the fish flakes easily with a fork. Avoid the steam when opening the packets. Served topped with scallions over rice.