Preheat oven to 375 degrees F. For each packet, lay out one piece of parchment on a flat surface with one of the sides toward you. Place a piece of fish in the center. Season with some of the salt and black pepper. Stack a few pieces of each vegetable on top of the fish. Drizzle with some of the oil, and top with garlic. Season with more salt and pepper. Starting with the side toward you, fold bottom edge of parchment up and over the fish. Fold the ends of the parchment in and over the fish. Roll fish in packet over once. Fold the corners on the top edge in toward the center to form a point (like an envelope). Roll up, tucking the pointed end in on the folded edge of the pouch.
Arrange all packets on a very large baking sheet and bake for 20 to 25 minutes or until fish flakes easily. Remove from oven and place each pouch on a serving plate. Carefully open pouch and serve with additional oil, lime wedges, and mint.