Scale the fish if necessary. Using the blunt side of a chef's knife, grab hold of the tail and scrape towards the head. It may be easier to wrap the tail in a towel to make it less slippery. Also, in order to minimise the mess, scale the fish out of doors or under running water in the sink.
For the next steps, make sure to use a flexible filleting knife.
Start by gutting the fish: place the tip of the knife in the vent hole, and work your way towards the bone behind the fish's jaw. Open the belly, and pull out the entrails. Wash or wipe the the cavity, and wipe dry with paper towels. This can be done by the fishmonger.
Make the first incision by cutting just behind the side fin, cutting down to the spine. Rotate the knife so that the blade is flat against the spine and then carefully work your way to the tail.
Alternatively, if this movement is too unwieldy, place the tip of the knife along the dorsal ridge. Using a short, slashing motion, cut along the dorsal ridge, making sure that the knife's tip is grazing the back bones. When the knife is level with the end of the belly, push the knife through so that the tip pokes out of the cavity. Pull the knife through to the end of the tail. It should feel like the knofe is scraping along the spine, in order to maximise the fillet's size.
Using your thumb, lift the upper half of the fillet so that you have aclear view of the belly end. Using the same slashing motion, graze the rib cage until the fillet lifts off the bones.
Turn the fish over and repeat on the other side.
Remove the rib cage, taking care to remove all of the small bones. Next, cut a v-shaped channel along the centre of the fillet to remove the pin bones.
Alternatively, use tweezers to remove the pin bones from larger fish, using the water to rinse te bones off the tweezers.
Trim the tail end of each fillet and the fish is ready to cook.
«Apply this technique to the preparation of any round fish such as sea bream, sea bass, mackerel, salmon, cod, pollock, trout, sardines and many more!»
A quick overview on how to fillet a round fish. As it can be difficult to visualise the process from reading instructions, you can use the following link to our handy video http://www.atelierdeschefs.co.uk/en/cooking-techniques/217-how-to-fillet-a-round-fish.php