1 Steam clams and mussels: Steam mollusks (clams and mussels) in a small amount of water (about two cups) until they just open. Set aside. Strain and reserve the cooking broth.
2 Prepare the cooked crab: Remove the crab legs from the body and use a nutcracker to crack the shells so that the meat can be easily removed once it is served (leave the meat in the shell).
Break the body in half, and then cut each half again into either halves or thirds. You can opt to keep the crab meat in the body segments and serve it that way (more work for the eater) or you can pick out the crab meat from the body segments.
If you pick out the crab meat, try to keep it in big chunks. Keep the top shell of the crab for making stock.
Note you can use prepared fish or shellfish stock, or you can make your own. If you are not making your own stock, you can discard the crab top shell body. If prepared shellfish stock is not available, I would combine some prepared fish stock (available at many markets, including Trader Joe's) with clam juice.
3 Prepare the shrimp: Split the shrimp shells down the back and remove the black vein. (See how to peel and devein shrimp.) I found the easiest way to do this, without removing the shell, is to lay the shrimp on its side and insert a small knife into the large end of the shrimp, with the blade pointing outward from the back (away from the shrimp and your hands).
Once you have split the shrimp shells, you can turn the knife toward the shrimp, and cut in a little to find the black vein. Pull out the vein as much as you can. You can probably also use a pair of kitchen scissors to cut the backs of the shrimp.
Alternatively, you can shell the shrimps and devein them. Shell-on imparts more flavor; shell-off is easier to eat.
4 Make the soup base: In a deep 8-quart covered pot, sauté onions and bell pepper on medium heat in olive oil until soft. Add the garlic, sauté 1 minute more.
Add tomatoes, broth from the mollusks, red wine, tomato juice, fish or shellfish stock, the herb bouquet, and salt and pepper to taste.
Bring to a simmer and cook, uncovered, for 20 minutes. Remove herb bouquet. Taste and correct seasoning.
5 Add fish and shellfish: Add the fish and cook, covered, until the fish is just cooked through, about 3 to 5 minutes.
Add the steamed mollusks, crabmeat, and shrimp. Heat just until shrimp are cooked (just 2-3 minutes, until they are bright pink). Do not overcook.
6 Serve: Serve in large bowls, shells included. Sprinkle with minced parsley. Serve with crusty French or Italian bread and a robust red wine.
Have plenty of napkins available, a few extra bowls for the shells, and nut crackers and tiny forks for the crab.