Bring a medium sized saucepan of salted water to a rolling boil. Slowly add the sliced potatoes to the pan. Cook until the potatoes are slightly translucent and soft. Do not overcook. Strain the water from the pan and let the potatoes cool. Wrap the tender potato slices around each fish fillet, until the fish is completely covered. Wrap each fillet tightly in plastic wrap so that the potatoes stick to the fish.
Heat enough vegetable oil to cover the bottom of a medium sized skillet over medium-high heat. Unwrap the fish fillets from the plastic wrap and brown each side of the fish. Reduce the heat and continue cooking the fish over medium-low heat until the bottom side is brown and the fish is cooked through.
Top with Horseradish Cream Sauce.
Melt the butter in a medium pan, then add the shallots and saute until tender. Slowly add the wine to the shallots. Reduce the mixture until it is nearly dry. Add heavy cream and allow the sauce to simmer until it is thick enough to coat a spoon, about 15 minutes.
Pour the cream sauce into a blender and add grated horseradish. Blend the ingredients together and then strain through a fine sieve. Add salt and freshly ground pepper, to taste.
Slice radishes and use for garnish.