Filipino Baked Milkfish (Baked Bangus)

2 pounds whole milkfish (bangus), or more to taste

1 tomato, diced

1 onion, chopped

1 (2 inch) piece ginger, thinly sliced crosswise, or to taste, divided

salt and ground black pepper to taste

4 calamansi, juiced

½ cup soy sauce

2 cloves garlic, chopped

Preheat the oven to 350 degrees F (175 degrees C). Line a roasting pan with enough aluminum foil to cover the whole bangus.

Remove scales and gills from bangus. Wash the innards. Pat fish dry with a paper towel.

Mix tomato, onion, and 1/3 of the ginger together in a bowl. Season with salt and pepper. Cut open the front side of the fish and fill with the tomato mixture. Place fish in the prepared pan.

Mix calamansi juice, soy sauce, garlic, and remaining ginger in a separate bowl. Pour over the fish in the pan. Fold foil over the fish and seal all ends.

Bake in the preheated oven until fish flakes easily with a fork, about 60 minutes.