Preheat the oven to 400°. Season cod all over with salt and pepper; sprinkle top of fish with chili powder.
Line the bottom of a baking dish with Sunkist California Star Ruby grapefruit slices and add dill sprigs and garlic. Arrange seasoned cod on top. Scatter jalapeño and grapefruit over fish, and drizzle all over with the olive oil and grapefruit juice.
Bake until fish is opaque and flakes easily with a fork, about 17 minutes.
Meanwhile, in a medium bowl, combine all the avocado salsa ingredients. Season with salt and pepper.
Serve cod with pan sauces spooned over top, and garnish with avocado salsa and more dill.
