In large saucepan, bring vinegars to a boil over medium-high heat. Add onions, garlic and rosemary. Cover and reduce heat; simmer 15 minutes. Uncover; increase heat to high and cook until most of vinegar is cooked off, about 5 minutes.
Add oil, salt and pepper to saucepan; cook 3 minutes. Add tomatoes, clam juice and white wine. Bring to a boil. Add orzo. Reduce heat; simmer, covered, until orzo is just tender, 8 to 10 minutes. Add fish; simmer, uncovered, just until fish is opaque and cooked through, about 3 minutes.
In small bowl, combine parsley and lemon rind. Stir into soup just before serving.