In a Dutch oven, saute onion in oil until tender. Add 1/2 teaspoon garlic; cook 1 minute longer. Add the tomatoes, lemon zest and pepper flakes; cook and stir for 2 minutes. Add the clam juice, wine or additional clam juice, tomato paste and salt. Bring to a boil. Reduce heat; cover and simmer for 10 minutes or until heated through., Add the fish, shrimp, scallops and parsley. Cover and cook for 8-10 minutes or until fish flakes easily with a fork, the shrimp turn pink and scallops are opaque. Combine mayonnaise and remaining garlic; dollop onto each serving.