Grilled Fish with Peperonata

Name: Grilled Fish with Peperonata
Ingredients: 4 tablespoons extra-virgin olive oil, divided; 3 cloves garlic, thinly sliced; 1 tablespoon fennel seed; Pinch of crushed red pepper; 1 medium red onion, thinly sliced; 1 teaspoon chopped fresh oregano; 1 teaspoon coarsely chopped fresh thyme; 1 teaspoon paprika; 8 cups thinly sliced bell peppers, any color; ¼ cup capers, rinsed; 2 tablespoons sherry vinegar; 1 ½ pounds skinned banded rudderfish, amberjack, swordfish or mahi-mahi; ½ teaspoon kosher salt; 1/4 cup chopped mixed tender fresh herbs, such as parsley, basil and/or mint; ¼ cup thinly sliced fennel