Boil the water, add the salt and make sure it is completely dissolved.
Add the quartered celery, fish heads and tails, finely chopped onion and parsley.
Boil over low heat for 20 minutes and remove the white foam with a spoon
(if the broth is not clear enough for your taste, you can strain it).
Then add the bay leaf and peppercorns and boil for another 5 minutes.
Increase the heat and add the fish, cleaned and cut into large pieces.
Cook for another 15 minutes, check the salt, then add the chopped herbs.