Preheat the oven to 400 degrees F. Place the ciabatta on a baking sheet. Drizzle with 1 tablespoon olive oil and sprinkle with 1 tablespoon each oregano and basil. Bake until golden brown, 15 minutes.
Meanwhile, heat the remaining 2 tablespoons olive oil in a large ovenproof skillet over medium-high heat. Add the garlic and anchovies and cook, stirring often, until the garlic is golden and the anchovies break down, about 3 minutes. Add the tomatoes, their juices and 1/2 cup water and bring to a boil. Reduce the heat to medium low and cook, stirring occasionally, until saucy, about 10 minutes. Stir in the olives, capers, red pepper flakes and the remaining 1 tablespoon each oregano and basil; simmer 2 minutes.
Season the fish with salt and pepper and arrange on top of the sauce in the skillet. Transfer the skillet to the oven and bake until the fish is just cooked through, 8 to 10 minutes. Divide the bread among 4 shallow bowls; top with the fish and puttanesca sauce.