In a 12 inch stainless steel skillet, heat the coconut oil over medium heat. Add the onion and saute the onion until the onion it starts to soften, about 2 minutes.
Add sliced bell pepper and green beans, and cook for 1 minute. Then add garlic, ginger, and chilies if using and saute for 30 seconds.
Add red curry paste, turmeric, cumin, and coriander, saute for 30 seconds. If necessary add a splash of water, and deglaze the pan.
Pour in the coconut milk, fish sauce, and add coconut sugar. Mix everything together and simmer until the coconut has completely melted, and the sauce slightly thickened. About 3-4 minutes.
Add the fish to the gently simmering curry, cover with the lid and allow to poach for 4 minutes. The internal temperature of the fish must reach 145°F (63°C).
Remove the skillet from heat, drizzle with lime juice and garnish with fresh chopped cilantro and thai basil. Serve warm over cooked jasmine rice.