This technique can be used for many types of fish, including bass, dorade, dentex, umbrine, mackerel, mullet, salmon, etc.
Lay the fish on a flat work surface and hold it by the tail with one hand. Gripping a knife with your other hand, scrape the scales off the fish starting working from the tail towards the head. Once the fish is perfectly descaled, rinse it under cold running water.
Using a sharp knife, make a deep cup in the fish from the head to the middle of the belly.
Carefully remove the guts.
Insert an index finger inside a gill and pull strongly to extract it completely. Then wash the fish under cold running water, both inside and out.
Using a knife, cut down to the bone behind the head.
Working parallel to the work surface, insert your knife in the flesh of the fish, just behind the head and above the spinal bone. Carefully move your knife back and forth in a sawing motion, moving it along the spine down towards the tail. Finish by detaching the upper fillet.
Turn the fish over and repeat steps 5 and 6. You can use the remaining fish bones to make fish broth.
Clean up the fillets by removing any membranes and the parts with blood.
Using tweezers, remove any small bones left in the fillets.