In a small saucepan combine the vinegar, the oil, the shallot, and salt and pepper to taste. In a small bowl combine well the mint, the basil, and the parsley and on each of 2 plates mound one fourth of the herb mixture. In a deep skillet bring 1 inch of salted water to a boil, add the scrod, skinned sides down, and poach it, covered, at a bare simmer for 8 minutes, or until it just flakes. Transfer each fillet with a slotted spatula, blotting it with paper towels and reserving the cooking liquid, to a bed of herbs and top the scrod with the remaining herb mixture. Add 1 tablespoon of the reserved cooking liquid to the vinegar mixture, bring the mixture to a boil, and spoon it over the scrod.
