Wash and clean the vegetables.

Boil them in salted water.

When they get tender, remove from water and place the fish in the stock. You can place it in a cheesecloth if you don't want any bones or scales in the broth. But even if you don't have a cheesecloth, pass the soup through a strainer when you remove the fish. Let the fish boil for about 15 minutes (it doesn't need long).

Remove the fish (if you didn't use a cheesecloth, pass the broth through a strainer) and add the rice.

When the rice is done, add the egg and lemon sauce. To make it, beat the eggs well in a largish bowl, add the lemon and temper it by gradually adding spoonfuls of the broth until the mixture reaches the right temperature, so that the eggs don't curdle. When it is hot enough start adding it to the soup, stirring constantly.

Serve the soup in deep plates with a few vegetables and a little cleaned fish in it (or let your guests add whatever they like).