Heat a large pot over medium-high heat. Add olive and diced onion and sauté for 3-4 minutes, stirring frequently. Add the garlic and cook 1 minute more.
Add the crushed tomatoes with their juices to the pot and stir well to combine with the onions. Once heated through, whisk in the tomato paste and add the fresh parsley, Italian seasoning, cherry tomatoes, and clam juice. Bring to a low boil.
Add the dry white wine and stir to combine. If the stew is too thick, add 2-4 cups water, or the desired amount of water to reach the desired brothy-ness. Return to a low boil.
Add the fish and cover. Reduce heat to low and simmer for 2-3 minutes. Add the shrimp to the pot, simmering for an additional 3 minutes. Season with salt and pepper, to taste. Top with your favorite store-bought or homemade croutons, if desired.