*Make a bouquet garni to use in the soup by tying together a few sprigs of parsley, rosemary, oregano and fennel with kitchen twine. Chop some additional fresh parsley to add to the soup just before serving.
Heat oil in a large pot over medium heat. Add the sliced fennel, chopped onion, chopped celery and salt. Sauté until the vegetables are soft, approximately 10 minutes.
Add the chopped garlic and the red pepper flakes and sauté for another 2 minutes. Stir in the tomato paste and then add the tomatoes (with juice), wine, clam juice, chicken stock, and a bouquet garni* of fresh herbs if desired.
Simmer to blend the flavors, about 20 minutes. Remove the bouquet garni. Add the clams to the cooking liquid, cover and cook until the clams begin to open, about 3 minutes. Add the prawns and fish and continue cooking about 3 minutes longer. Just before serving, stir in the dungeness crab meat, a handful of fresh parsley, and the lemon juice. Ladle into bowls and serve!