Cook the rice in boiling salted water for about 15 minutes. Then drain. Wash the fish fillet, dab dry and cut into cubes. Sprinkle with lemon juice. Put into boiling salted water.
Allow to stand for approx. 8 minutes at low heat. Then also drain. Peel and chop the carrots. Wash and quarter the apple, remove the core. Cut apple into slices. Dice gherkins.
Wash the chives and cut into fine rolls. Mix yoghurt, mayonnaise and mustard. Mix the prepared ingredients with the capers. Carefully fold in the fish. Season to taste with salt and pepper.
Let the salad steep a little.