Peel and roughly dice the onion. Peel and slice the garlic. Clean, wash and slice the tomatoes. Clean, wash and cut the fennel into thin strips. Put fish pan and 150 ml water in a pot.
Bring to the boil at high heat and simmer for about 4 minutes at medium heat. Stir carefully several times. In the meantime heat up the oil in a pan. Brown the onion, garlic and fennel.
Add the tomatoes and fry for about 2 minutes, turning. Deglaze fish pan with broth, bring to the boil and add the fried vegetables. Season soup with salt and pepper. Wash the dill, dab dry and chop finely.
Serve the soup sprinkled with dill and garnished as desired with dill blossom.