Clean the perch from the scales, remove the tail, gills and entrails. Cut off the heads they will go to the broth, rinse well under running water. Pour water into a pan, add peeled and coarsely chopped carrots, whole onions, bay leaves and cook for 10 minutes, then add heads, salt and pepper to taste, cook for 15 minutes. Strain the broth and return to the pan, leave a little broth to soak the gelatin. Put perch in the broth and simmer for 20-25 minutes.
Pour gelatin over with cooled broth and leave to swell for 10 minutes. Then dissolve in a water bath.
When the fish is cooked, remove it from the pan, let it cool slightly and separate the meat from the bones.
Put the fish in plates, paint on top with lemon slices and, if you wish, sprigs of greenery. Mix gelatin with strained fish stock and pour perch. Refrigerate until completely frozen.
Jellied river bass is very tasty, rich and aromatic. River bass has white, tender, juicy and non-greasy meat. The broth based on heads and vegetables should turn out to be light, and if you suddenly get dark just add beaten egg white, leave for a few minutes and strain through a very fine full or gauze folded in several layers. The broth can darken only in two cases - if there was a big fire or cooked for a long time. This dish is perfect for any festive table.