Brown fine chopped onions in half of the olive oil. Add about 3 glasses of water and cook for a while. Press through a strainer using a wooden spoon. Place potatoes and carrots cut into pieces, tomatoes and onion puree in a large pan. When the vegetable is tender add pieces of grey mullets (or any other deep water fish) cut crosswise into pieces. Cover and cook for about 20 minutes.

Pour lemon juice after taken off the fire and leave for cooling. Decorate with slices of lemon and parsley.