In a heavy-bottomed stock pot or Dutch oven over medium-high heat, add oil and heat until shimmering. Add onion and cook, stirring often, 5 minutes or until softened. Add the garlic and cook, stirring 1 minute or until fragrant.
Reduce heat to medium. Add ⅓ cup parsley, and tomatoes with juice; cook, stirring occasionally, for 12 minutes or until flavors are melded.
Add oregano, thyme, clam juice, wine, and fish. Cook gently, 5 minutes or until fish is opaque and flakes easily when tested with a fork. Stir in cayenne pepper. Season to taste with salt and pepper. Sprinkle with chili peppers (if using) and remaining parsley. Ladle into bowls and serve garnished with lime wedges, if using.