1. In a skillet, sauté the onion in the margarine (oil), until soft.
2. Combine the onion with the carp and whitefish and chop finely with steel blade in food processor (or chop by hand).
3. Put the mixture in a bowl and season with salt and pepper to taste.
4. Add the eggs and mix well to blend. Blend in the almonds.
5. With wet hands, shape the fish mixture into ovals, using 2 tablespoons for each.
6. Place the ovals in a pot of lightly boiling fish stock, cover and cook at a slow boil for about 30 minutes.
7. Remove the fish balls from the bouillon and arrange on a serving dish.
8. Strain the bouillon through a fine strainer over the fish and refrigerate. The bouillon will jell.
9. To serve, arrange one or two cooked carrot slices on each piece of gefilte fish, decorate with parsley and serve horseradish on the side.