Heat oil in a pan over medium heat. Fry onion, serrano peppers, garlic, ginger, cinnamon bark, curry leaves, and cloves until onions are lightly browned, 3 to 5 minutes. Add dried fish, chili powder, curry powder, and turmeric. toss until evenly combined.
Mix mangoes into the pan. Add water and cook until mangoes soften, 10 to 15 minutes. Add coconut milk and season with salt. Simmer 5 to 10 minutes more until flavors are well combined.
