Clean the fish and wash thoroughly. Salt it and leave in colander to drain well. Scour the fish, the onions, the potatoes, the celery, the carrots and the zucchini. Put them in a pot with 2 liters of clean water. Then add the oil, salt and pepper. Boil over medium heat for about half an hour.
As soon as they begin to soften (do not boil) put the fish in the pot carefully and let them boil for about 20 minutes. Remove the fish from the pot carefully and place it on a platter. Then remove vegetables with a slotted spoon and place them next to the fish on the platter. Throw the rice in the pot and if necessary fill out some extra hot water. Boil the rice until it softens. Dissolve the corn flour in ½ cup of cold milk, beat the egg yolks with the lemon juice and then add the dissolved corn flour. Add in the mixture some broth from the pot with a spoon, while stirring slowly.
Then add the sauce into the soup.
Dangle the pot so the sauce can cover everything and let it boil.
Remove from the heat.
This is a very tasty way of cooking fish, a valuable food in our diet. Fish is an excellent source of omega-3 fatty acids. The omega-3 fatty acids reduce elevated triglycerides, increase the vasoprotective HDL (good) cholesterol and reduce platelet aggregation in vascular walls offering antithrombotic action. Apart from the positive effects on the cardiovascular, omega-3 fatty acids, contribute positively to conditions such as asthma and rheumatoid arthritis.