In a large heavy-bottomed or clay pot, heat olive oil over medium heat. Once shimmering, add onion, celery, and carrot. Sauté for about 5 minutes until the onions are soft.

Stir in minced garlic, bay leaves, and red pepper flakes. Continue to sauté for another 2 minutes until fragrant.

Add canned whole peeled tomatoes, stirring well. Bring to a gentle simmer, then reduce heat to low. Let simmer uncovered for about 15 minutes.

Fold in chunks of firm white fish and drizzle with white vinegar. Cook uncovered for about 10 minutes until most liquid evaporates and fish is cooked through.

Pour in fish stock, stirring well. Cover the pot and reduce heat to low. Allow to simmer for 10 minutes.

Stir in fresh clams and cook until they open, about 3–5 minutes. Add peeled shrimp and cook until pink, around 3 minutes more. Season with salt and pepper.

Ladle the stew over slices of toasted Italian bread to serve.