In a large skillet, heat the olive oil over medium heat. Add the chopped onion and sauté until soft and translucent, about 5 minutes.
Add the minced garlic and grated ginger to the skillet, stirring for about 1 minute until fragrant.
Stir in the korma curry paste, mixing well to combine with the onion, garlic, and ginger. Cook for another 2 minutes to release the flavors.
Pour in the coconut milk, stirring to incorporate the curry paste completely. Allow the mixture to simmer for about 5 minutes.
Cut the fish fillets into bite-sized pieces and gently add them to the skillet. Cook for an additional 5-7 minutes, or until the fish is opaque and flakes easily with a fork. Season with salt and pepper to taste.
Remove from heat and garnish with fresh coriander. Serve the fish korma over cooked basmati rice or quinoa.