Combine tomatoes, bell pepper, onion, celery, seafood stock, tomato paste, wine, garlic, Italian seasoning, sugar, bay leaf, and crushed red pepper flakes in a large slow cooker.

Cover and cook on LOW for 6-8 hours or on HIGH for 3-4 hours (or until vegetables are tender).

Turn the slow cooker to HIGH heat. Stir in the shrimp, fish, crabmeat and clams. Cover and cook on HIGH for 20-30 more minutes (stirring twice), or until shrimp is opaque and fish flakes easily with a fork. Remove bay leaf.

Just before serving, stir in basil and parsley. Season with salt and pepper, to taste.

Heat 2 tablespoons of olive oil in a Dutch oven or large soup pot over medium-high heat. When the oil shimmers, add the bell pepper, onion, and celery. Cook, stirring regularly, until the vegetables start to soften, about 5-7 minutes.

Add the garlic and tomato paste; cook, stirring constantly, for 1 more minute.

Stir in the tomatoes (with their juices), stock or broth, wine, Italian seasoning, sugar, bay leaf, and red pepper flakes.

Bring the liquid to a boil, then reduce the heat to low, cover the pot, and simmer gently for 15-20 minutes.

Add the shrimp, fish, crab, and clams (with their juices). Bring to a simmer, lower the heat, cover, and cook for 8-10 minutes, until the shrimp are pink and the fish flakes easily with a fork. Stir the pot gently so that you don't break up the fish.

Remove the bay leaf.

Just before serving, stir in basil and parsley. Season with salt and pepper, to taste.