Finely grate enough peel from 2 limes to measure 1 1/2 teaspoons. Squeeze enough juice from 2 limes to measure 2 tablespoons. Cut third lime into wedges.

Heat vegetable oil in large saucepan over medium-high heat. Add chopped shallots, diced red bell pepper, and minced ginger; sautè until shallots are tender and peppers soften, about 5 minutes. Stir in curry paste, coconut milk, fish sauce, 1 1/2 teaspoons lime peel, and 2 tablespoons lime juice. Simmer gently, stirring often, about 5 minutes. Sprinkle fish and shrimp with salt and pepper. Add fish and shrimp to curry sauce. Return to very gentle simmer and cook just until fish and shrimp are opaque in center, 5 to 6 minutes. Season to taste with salt and pepper. Gently stir in cilantro and basil; serve with lime wedges.