Peel the eggs, peel the cooled potatoes. Cut the bismarck herring, eggs and potatoes into strips of the same size. Cut the onion, apple and pickles into smaller pieces and place in a bowl with the peas.
Then season with the vinegar from the cucumber and herring jar, add salt, pepper, dill and mustard to taste. Finally, add the sour cream and natural yoghurt and mix everything together (if you want the rich variant, take a cup of creme fraiche, sour cream and mayonnaise instead of sour cream and yoghurt).
Then chill for at least 4 - 5 hours. The fish salad can be prepared the day before. Let it stand at room temperature before consuming it so that it is not too cold. I serve fresh baguette with it.