In a mortar and pestle, crush the anchovies and minced garlic together until it forms a paste. (You can use a small bowl and a fork if you don't have a mortar and pestle.) Set it aside.
In a large pot, heat olive oil over medium heat.
Add fennel, shallots, tomato paste and crushed red pepper to the pot. Season with kosher salt & fresh cracked pepper. Saute until tender, 5-7 minutes.
Add the garlic-anchovy paste and cook for another minute.
Add the white wine and increase the heat to medium-high. Reduce it by half.3
Add the thyme, bay leaf, clam juice, stock, tomatoes & sugar. Allow it to come to a boil, reduce the heat to a simmer, cover the pot and cook it for about 30 minutes. Taste and adjust the seasoning to your liking.
Meanwhile, heat your oven to 350 degrees. Drizzle a little olive oil on your ciabatta slices and toast them for 5 to 7 minutes.
Add the mussels, return the lid and cook for about 3-4 minutes. Add the shrimp, and the fish on top, cover and cook for another 3-5 minutes until the mussels have opened and the shrimp and fish are cooked, but still tender.
Discard the bay leaf. Distribute the stew into bowls and garnish with fresh parsley. Serve with ciabatta toasts.