Peel and cut potatoes into small pieces. Cook in salted water for 10 minutes. In large sauce pan, add oil, garlic, onion, cook over low heat. Add can tomatoes and 1 can water. Add oregano, parsley, salt, pepper. Simmer for 1/2 hour. Add drained potatoes to tomato mix, simmer for 5 minutes. Add rinsed fish to sauce pan. Cook for 10 minutes until potatoes and fish are cooked. Add salt and pepper to taste. Serve in large soup bowls with Italian bread.