Wash potatoes, boil until tender, cool, cut into halves or quarters. Chop green onions, add to potatoes. Mix vinegar with salt, pepper, sugar and butter, pour over prepared marinade potatoes. Rinse and shake off the dandelion leaves and corn salad, then add to the potatoes. Drain monkfish fillets, salt, pepper, season with lemon pepper and fry in melted butter on both sides, served with potato salad.