For the halibut, pour ginger ale into a wide, shallow dish and set aside for 1 hour to go flat.

Stir in cilantro and ginger to make a marinade, then add halibut fillets and turn to coat all over.

Cover dish with plastic wrap and refrigerate for 2 hours.

Meanwhile, for the mango-serrano pico de gallo, put red bell peppers, mango, green onions, lime juice, Serrano peppers, and salt and pepper into a medium bowl and toss to combine.

Cover with plastic wrap and refrigerate until ready to use.

Prepare a grill for medium heat cooking, oiling the grill grates as needed.

Lightly brush fillets with a bit of the oil, then arrange on the hot grill.

Cook about 7 inches over gray flaming coals, flipping once, until cooked through, 3 to 5 minutes per side, rotating each fillet a quarter turn after 1 1/2 minutes on each side to create attractive grill marks, if you like.

Serve fillets topped with mango-serrano pico.