In small saucepan cook onion and green pepper in butter till tender but not brown.
Stir in tomatoes, olives, sugar, 1/4 teaspoon salt, garlic salt, and dash pepper.
Simmer till thickened, about 15 to 20 minutes.
Panfry fish according to package directions.
Butter buns, if desired.
Place fish portions on bottom halves of buns.
Spoon some sauce over fish, then put tops of buns in place.