Horse mackerel - filleting
Remove scales (de-scale)
Spread a newspaper out over a cutting board and place the horse mackerel down. Move the tip of the knife from the tail towards the head to scrape off the scales.
Remove scutes (curved lateral line of hard scales)
Make a small angled cut with the tip of the knife from the tail and scrape off the scutes. Repeat in the same manner for the other side of the fish.
Chop off the head
Place the knife behind the pectoral fin and make an incision in the direction of the head with the knife at an angle (parallel to the gills). Slice in approximately half-way and then turn the horse mackerel over and repeat in the same manner on the opposite side making an incision with the knife to chop off the head.
Remove the innards
Insert the tip of the knife into the belly and make a shallow incision up to the anal fin, open the belly and remove the innards. At this point wrap up the innards in a newspaper, throw these away and rinse the horse mackerel with water and pat dry to remove excess moisture.
Fillet into 2-layers
Insert the knife from the flank until it reaches the backbone and slide the knife towards the head of the fish. Turn the horse mackerel over and repeat with the knife in the same manner from the belly. Lastly insert the knife facing the tail and slide it along the backbone to completely remove the fillet. Now you have a 2-layer fillet.
Fillet into 3-layers
Place the 2-layer filleted horse mackerel with the bones facing downwards, insert the knife from the flank until it reaches the backbone, slide the knife towards the tail to make an incision. Turn the horse mackerel over and make an incision with the knife in the same manner. Insert the knife at the base of the tail and slide it along the top of the backbone to remove the fillet from the backbone. Now you have a 3-layer fillet.
Remove the stomach bones
Lay the knife parallel to the cutting board and slice away the stomach bones.
Pull out small bones
Pull out small bones remaining in the mid-section of the fillet. These can be easily removed when pulled out in in the direction of from tail to head. To ensure no small bones go unnoticed, confirm with your fingers as you work to pull these out.
Remove the skin
Start skinning from an incision near the head and strip off the skin in the direction towards the tail.