Thaw fish, if frozen. Rinse fish; pat dry with paper towels. Using a sharp knife, make bias cuts about 3/4 inch apart into the fish fillets. (Do not cut completely through fish.) Tuck one or two basil leaves into each cut. Rub fillets with ginger.
Place sweet peppers and asparagus in a steamer basket. Place fish on top of vegetables. Place basket into a large, deep saucepan or wok over 1 inch of boiling water. Cover and steam for 6 to 8 minutes or until fish begins to flake when tested with a fork.