Green Posole with Cod and Cilantro

Name: Green Posole with Cod and Cilantro
Ingredients: 2 tablespoons olive oil; 2 shallots, chopped; 3 garlic cloves, finely chopped; 2 serrano chiles, thinly sliced, divided; 8 medium tomatillos (about 1 1/4 pounds), husks removed, rinsed; Kosher salt, freshly ground pepper; 1 cup cilantro leaves with tender stems, plus more for serving; 1 pound cod fillet; 1 (15-ounce) can white hominy, rinsed; 1 (8-ounce) bottle clam juice; 3 small radishes, trimmed, thinly sliced; Lime wedges (for serving)