Peel, wash and slice the potatoes. Drain beetroot and cucumber. Heat half of the fat in a coated pan and fry the potatoes in it for about 10 minutes, turning them until golden brown.
In the meantime, cut the fish into pieces. Wash the chives, dab dry and cut into small rolls. Whisk eggs and milk, season with salt and pepper. Stir in fish and chives.
Season potatoes with salt and pepper. Add the remaining fat, pour the scrambled egg mixture over it and let it set at a mild heat. Use a spatula to gently push the mixture together. Add beetroot and cucumber slices to the potatoes.
Season with salt and pepper.