For the coulis: Combine the mango, orange juice, 1/4 cup water, ginger, salt and pepper in a blender. Blend until smooth and pour into a small saucepan. Cut the vanilla bean in half lengthwise and scrape the seeds into the saucepan using a paring knife. Add the empty vanilla pods. Bring the mixture to a boil over medium-high heat. Reduce the heat and simmer, about 6 minutes. Remove and discard the vanilla pods. Whisk in the butter until smooth.
For the fish: Heat the butter and oil over medium-high heat in a 12-inch nonstick skillet. Sprinkle the fish with the salt and pepper on both sides. Cook the fish until the fish flakes easily with a fork, 6 to 8 minutes on each side.
Arrange the fish on a platter and spoon the coulis on top.