Thaw fish. Cut into 1 inch pieces.
Coat fish with 3 tablespoons of the cornstarch. Set fish aside.
Cut bell pepper into 3/4 inch squares. Set bell pepper aside.
Drain the pineapple, reserving the juice. Combine the pineapple juice, remaining 1 tablespoon of cornstarch and pepper.
Stir in soy sauce, honey, ketchup, vinegar and sherry. Set bowl aside.
In a wok or electric skillet cook fish in hot oil about 1 minute on each side; remove fish from skillet.
Add pepper squares to skillet; stir-fry about 2 minutes. Remove peppers from skillet.
Add pineapple juice mixture to skillet; cook and stir until thickened and bubbly.
Add pineapple to skillet; stir in fish and pepper. Heat 1 minute. Serve over hot cooked rice.