Wash potatoes thoroughly and cook in boiling water for about 20 minutes. Peel the cucumbers and use a vegetable slicer to slice them lengthwise into strips up to the core. Salt the cucumber strips slightly and let them stand for about 10 minutes.
Prepare the fish in a preheated oven according to the package instructions. Meanwhile drain, rinse and peel the potatoes. Mix quark, dill and cucumber. Season with salt and pepper. Arrange potatoes, cucumber salad and fish on plates.
Sprinkle with pink berries.