Mussels are usually debearded when purchased, but if they still have them, remove them just before cooking and rinse lightly under cold water. Refrigerate until ready for use.
Peel and devein shrimp. Refrigerate until ready for use.
Cut fish into 2 inch, bite-sized pieces. Refrigerate until ready for use.
Heat the oil in a stock pot over medium heat.
Add the fennel, onion, shallots, and salt, stirring until it softens, about 10 minutes.
Add the garlic and red pepper flakes. Stir and cook for 2 minutes.
Stir in tomato paste, tomatoes with juice, clam juice, bay leaf, and red wine.
Cover and bring to a simmer.
Reduce the heat to medium low and let simmer for 30 minutes.
Add clams and mussels. Cover and cook, about 5 minutes, until clams and mussels have opened.
Add fish and shrimp and stir very gently, cooking for about 5 minutes.
Any clams or mussels that have not opened should be discarded.
Serve cioppino in bowls with bread on the side for dunking.