Rub fish with turmeric and salt and fry lightly in hot oil.
Remove from pan. Place red curry paste and onions in pan stirring constantly until fragrant. Add grated lime rind, coconut milk, 1 cup of water, whole chillies and fish sauce. Simmer uncovered for 10 minutes.
Add fish and continue to simmer for a further 10 mins. Stir in lime juice and basil leaves and serve at once with steamed rice.