With a sharp knife or kitchen scissors, prepare the fish by trimming the fins and tail of the milkfish.

Split milkfish on the top side starting from the tail to the head by running the edge of the knife along the belly.

Lay fish open, then remove gills and innards. Wash the fish in running water to remove blood.

Remove backbone by laying fish flat on the cutting board with the skin down. Hold the knife in a slanted position the cut in with the tip of the blade along the backbone from the head to tail.

Add 2 cups of vinegar, sliced garlic, and onion into a bowl.

Mix the ingredients well then season with 2 tsp salt and ¼ tsp ground pepper and stir until the ingredients are well incorporated.

Dip the milkfish until all the parts are soaked, then marinate for about an hour.

Heat olive oil on medium heat.

Once the oil is hot, pan-fry the fish skin side down for about 10 minutes.

Turn the fish over using a wide spatula to cook the opposite side until golden brown for about another 10 minutes.

When the fish is ready, transfer it to a plate and serve it fresh.