Remove the gills and innards of the bangus but not the scales. Using a scissor or knife, cut the fins and tails. Wash fish thoroughly, drain, and slice diagonally.
In a casserole, put in the garlic, onion, and ginger.
Arrange sliced bangus, and add water, vinegar, salt, peppercorn, and cooking oil.
Cover and simmer for 10 minutes.
Put the vegetables and long green pepper in. Cover and simmer at a medium heat for another 5 minutes.
Remove from heat and serve. Enjoy!