Heat olive oil in a large pot over medium heat. Add onion and bell pepper; sauté until softened, about 5 minutes. Add garlic and cook for another minute.
Stir in crushed tomatoes, tomato sauce, broth, wine, basil, oregano, red pepper flakes, salt, and black pepper. Bring to a simmer and cook for 30 minutes, stirring occasionally.
Add the clams and mussels to the pot. Cover and cook for 5 minutes until they start to open.
Add the shrimp, scallops, and fish. Simmer gently for 5-7 minutes, or until the seafood is cooked through and the fish flakes easily with a fork.
Discard any clams or mussels that do not open.
Serve hot, garnished with fresh parsley and lemon wedges.