If fish fillets are large, cut into 5 serving pieces.
Mix soy sauce, garlic and ginger; brush on both sides offish.
Cook and stir green peppers and mushrooms in oil in 10-inch skillet over medium-high heat until crisp-tender, about 6 minutes.
Remove vegetables with slotted spoon; reserve.
Fry fish in same skillet until fish flakes easily with fork, about 8 minutes.
Add vegetables; heat just until hot.