Cut the bangus at the dorsal or back side from head to tail. Then clean it by removing scales, bones, innards and gills.
Wash and drain and put in the colander to drain excess water until dry.
In a bowl, combine chopped salted egg, onion, celery, tomatoes, patis and ground black pepper.
Cut a piece of banana leaf into 1 foot long then wash and wipe dry. Lay the banana leaf on a clean surface.
Put the butterflied bangus on top of the banana leaf. Then stuff it with the tomatoes-salted egg mixture by putting it in the center of the fish from head to tail.
Fold the bangus to wrap the mixture and roll it in the banana leaf to wrap the fish.
Tie the head, tail and the center part of the fish with pieces of banana leaf.
Heat 2 to 3 cups of cooking oil in a big wok or kawali that can fit the bangus.
Put in the bangus and fry then cover immediately to avoid oil splatters. Fry until the cracking noise of the hot oil is almost gone.
Then turn the fish to fry the other side also. When cooked, remove from the wok and transfer to a plate.
Remove the banana leaf from the fish and serve hot with your favorite dipping sauce or side dish.