Cod with Clams and White Wine

Name: Cod with Clams and White Wine
Ingredients: 6 cups cold water, plus more as needed; 3 tablespoons plus 1/2 teaspoon kosher salt, divided, plus more as needed; 1 pound littleneck clams, scrubbed; 4 (6-ounce) skinless cod fillets (about 1 1/4 inches thick); 1/4 teaspoon black pepper; 1 tablespoon all-purpose flour; 2 tablespoons extra-virgin olive oil, divided; 2 garlic cloves, minced; 1/2 cup (4 ounces) dry white wine; 1/2 cup bottled clam juice; 3 tablespoons cold unsalted butter; 2 tablespoons chopped fresh parsley, plus more for garnish; Pinch of smoked sweet paprika; Crusty bread, for serving