3 large limes
1 tablespoon vegetable oil
1 cup chopped shallots
1 large red bell pepper, cut into 1/2-to 3/4-inch dice
1 1/2 tablespoons minced peeled fresh ginger
2 1/2 teaspoons Thai red curry paste (such as Thai Kitchen brand)
1 13 1/2- to 14-ounce can unsweetened coconut milk
1 tablespoon fish sauce (such as nam pla or nuoc nam)
16 to 18 ounces halibut fillets, cut into 1 1/2-inch chunks
8 peeled deveined uncooked large shrimp (8 to 10 ounces)
1/3 cup chopped fresh cilantro
1/3 cup chopped fresh basil