The night before you make the gefilte fish, fillet the fish and place the fillets in a shallow bowl. Salt them lightly.

The next day, grind the fish fillets in a food processor along with 3 of the onions and 3 of the carrots.

Transfer the mixture to a bowl and add the eggs, matzo meal, 1/4 cup water, salt, pepper, and sugar. The mixture should be fluffy and slightly sticky. Set aside.

Put the reserved head, bones, skin, and trimmings from the fish in a large soup pot along with the remaining carrot and onions, the parsley, celery, lemon slices, remaining water, and salt to taste.

Bring to a boil and simmer, covered, for 15 minutes over low heat.

Wet your hands and shape the fish mixture into 3 inch patties. Place patties in the simmering broth; add more water to cover the patties, if necessary. Cover pot and simmer fish patties for 1 hour.

Turn off the heat and let the patties cool in the broth. When cool, carefully remove them with a slotted spoon to a serving dish. Strain the broth, then pour it over the patties. Garnish with carrot and onions from the broth.

Serve warm or cold, decorated with thin slices of carrot. When served cold, the liquid will jell.