Fry the rice in a pan with a little olive oil until translucent. Deglaze with the water and add about 1 teaspoon of salt. Bring to the boil briefly and simmer until the water is soaked up.
Cut the onion into rings that are not too thin. Fry in a non-stick pan with olive oil. Add the fish fillet and fry for 2 minutes on both sides. Season with salt and a little pepper. Add the peas and fry for 3 - 4 minutes over medium heat. Add milk and cream and simmer for 3 - 4 minutes.
Remove the stalks from the dill, chop and pour over the fish.