Unless you are an avid fisherman and catch it yourself, it is entirely possible that you could go your entire life without ever having to clean or fillet a whole fish.

The reality is that most fish are just too large for the average person to purchase whole and then cut into pieces. If you have ever seen a tuna at the aquarium you know what I mean. They can be HUGE. It is quite possible that you might find yourself with a whole salmon after a day of sport fishing or a trip up the Copper River. But, more often than not, if the recipe calls for a lot of salmon, you will purchase a whole side of salmon that your butcher has already filleted for you—not the entire fish.

There are some fish that are commonly sold whole like snapper and trout. Though you can obviously purchase these same fish already filleted, it can be cheaper and tastier to purchase them whole and cook them that way. But, those who prefer the elegance and ease of a fillet may benefit from learning to fillet the fish themselves while saving a little money. Once you get the hang of it, filleting your own fish will take no time at all.

How to Fillet a Fish
Having a very sharp flexible filleting knife is the key to filleting any fish quickly and without destroying the fish. Once you have that, follow these steps. 

Fillet the first side
Slide your sharp fillet knife diagonally along the base of the head of the fish down to the bones.

Slide the knife along the length of the back of the fish above and parallel to the backbone about 1/2 inch into the fish.

Repeat this motion as you move farther down the backbone folding the top fillet back with your free hand as you go.

Slide the knife along the ribs, leaving them attached to the skeleton and detach the top fillet.

Fillet the second side
Turn the fish over and around so that the tail is facing away from you. Make a diagonal slice down to the bone at the base of the head like you did in the first step.

Starting at the tail, slide the knife along the back cutting about 1/2 inch deep along the upper side of the bones. Repeat the motion folding back the fillet until the central backbone is exposed.

Slice in the opposite direction along the ribs, detaching the second fillet.

Skin the fillets
Place the fillet skin side down on a cutting board. With a very sharp knife, cut just above the tail down to the inner part of the skin.

Grip the skin with your free hand and move it from side to side while pulling on the skin. Hold the knife firmly and almost flat. You now have beautiful skin-free fillet.

In the world of performance cutlery, there are two types of chef knives that serve as multipurpose tools in the kitchen: the classic Western-style chef’s knife and the Japanese-style Santoku knife. While both chef knives are similar in purpose, they definitely have their differences, from the shape and design to cutting styles and techniques, at https://viebelles.com/blogs/taste/santoku-knife-vs-chef-knife-the-difference you will check the difference between them.

This might be tricky to picture, so here is a video illustrating the process. If you watch it once, the instructions will be much easier to understand.