1. Boil fish with ginger in water for 10 minutes. Drain, flake meat, and discard bones. Season with salt and pepper. Blend well with the rest of the ingredients except ingredients for sauce.
2. Form every tablespoon of mixture into balls. Deep-fry until golden brown. Set aside.
3. Sauce: Combine the first 3 ingredients and reserved pineapple syrup. Season with pepper and soy sauce. Simmer. Add dissolved cornstarch and simmer, stirring constantly until cooked. Add bell peppers and green onions. Pour over fishballs just before serving.
Ginger helps remove the fishy smell of fish and adds a fresh and spicy note. To infuse flavor into the fish, slice the ginger thinly so that there is more surface exposed in the water while it boils.
Fish are a good source of protein that help repair body tissues. This dish also contains vitamin A which is important for normal vision and healthy skin.