Lampuca Sicilian Fish Stew

Name: Lampuca Sicilian Fish Stew
Ingredients: 1/4 cup extra-virgin olive oil; 2 pounds sweet Italian sausage, casings removed and crumbled; 4 cloves garlic, smashed; 1 large Spanish onion, roughly chopped; 1 teaspoon crushed red pepper flakes; 2 anchovy fillets; 1/2 cup white wine; 1 lemon, juiced; 2 cups chicken stock; 2 cups tomato sauce; 1/4 cup raisins; 3 tablespoons harissa, plus more for serving; 30 littleneck clams; 20 fresh mint leaves, torn; 2 mahi mahi fillets, cut into large chunks; 4 slices bread, toasted