Soak barley and lentils for one night (lentils conditionally necessary, see package).
Gut and scale fish.
Bring water to a boil with the additions and simmer gently for at least an hour until the fish falls apart. Remove bones as best as possible. Add the finely chopped dill and a little salt if necessary and serve hot.
(*) White goosefoot often grows in cities on rubble heaps. In spring the tender shoots can be collected, in summer and autumn the flower panicles or the starchy seeds.
Tip: For the soup use all possible fish scraps, as they arise in the kitchen or are possibly available in fish stores at a reasonable price. If you don’t want to go to the trouble of removing the bones with every bite, you can of course also use fish fillets.