Heat the oven to 375 F.
In a small bowl, add the lemon wedges, sugar and salt. Toss gently to coat evenly. Place the lemons in a shallow baking dish and cover with aluminum foil. Roast until soft and slightly browned, about 1 hour.
Heat the broiler (grill). Position the rack 4 inches from the heat source. Lightly coat a baking pan with cooking spray.
Place the fish fillets in the prepared baking pan. Brush with canola oil and top with garlic. Broil (grill) until the fish is opaque throughout when tested with the tip of a knife, about 5 minutes on each side.
Transfer the fish to individual plates. Squeeze 1 roasted lemon wedge over each fillet and sprinkle with parsley. Serve with another roasted lemon wedge on the side.