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What Is a Fillet Knife? (A Complete Guide For Beginners)

A fillet knife is also referred to as a filleting knife. It is used for the filleting and preparation of fish. The blades of this knife are usually 15 to 28 cm and 6 to 12 inches long. The knives provide a lot of control when filleting.

This makes the process simple and faster in food preparation. It is made of long-lasting materials. This makes it have a longer lifespan even after frequent use. Fillet knives can also be utilized on fruits and bread cutting. They are simple to grip and maneuver.

What Is a Fillet Knife?

What is a fillet knife

A fillet knife is a knife that has a thin flexible blade, commonly 6 to 12 inches long for filleting and skinning fish. The design of its blades allows the knife to elegantly budge along the backbones of the fish inside and the surrounding parts by the side of the bones. It justly slices through the skin, separating it from the flesh.

Related – 10 Best Fish Fillet Knives In 2021 – Reviews & Guide

What Does a Fillet Knife Look Like?

Fillet knives are thin and flexible. The blade normally measures between five to nine inches. They present an outstanding upward curve on its length and a sharply curved tip.

What Is a Fillet Knife Used For?

Fillet knives are used for;

  • Prepping fish
  • Skinning of the fish
  • Mincing of onions
  • Making of delicate cuts
  • Filleting of small and medium-sized fish fillets

How to Use a Fillet Knife?

For you to accomplish the preparation of an accurate cut of fish, this knife would be a better option. The knife’s lengthy, slender, bendable but tough blade cuts fish simply. When using it on the fish, the following procedure should be adopted;

Fish exterior 

  • Use the backside of the blade to remove the scales of the fish
  • Get rid of the fins
  • Skin taking off
  • Removing of the entrails

Fish interior 

  • Cut the fish end-to-end
  • Cut on each side to set out the fillets
  • Use the bendable blades to swiftly remove the fillets from the backbone
  • Repeat on the other side to remove the other fillet.

What Is the Right Size of a Fillet Knife?

What is the right size of a fillet knife

Fishing filleting knife sizes vary according to the kind of fish that you want to fillet. The usual rule is that the knife should be at least 2 inches longer than the fish. This is to allow enough room for movement while slicing through the fish’s sharp bones.

The fish fillets ordinarily vary between 6 to 12 inches in length. There are shorter knives of 4 to 6 inches long used for smaller fishes such as trout, perch, or mackerel.

For a versatile knife that can be used in all sizes of fish, it is advisable to go for 7 to 8 inches long. This size is perfect for medium-sized fish such as salmon, trout, or catfish.

Besides, bigger fishes such as halibut, codfish, or tuna, a knife that is 8 inches long are the most ideal.

How to Sharpen a Fillet Knife?

How to sharpen a fillet knife

Maintaining your fishing knife sharpness is fundamental to getting the best fillet and getting the maximum flesh from the fish frame.

When sharpening the fillet knife, there are few ways you can easily hone your filleting knife blade. These are;

Use of an electric sharpener

This is by far the easiest way to sharpen a fishing knife. An electric sharpener makes it so simple. The electric sharpener has two methods that involve sharpening and removal of steel from the edges of the blade and the other one being honing.

This does not depend on the model of your sharpener. When sharpening, follow the below procedure;

  • Pull the knife-edge crosswise of the sharpening stage i.e., the thin slot on the top of the sharpener. This procedure should be done repeatedly to achieve your desired results?
  • Honing stage. Pull the knife-edge crosswise. Bring back the edge of the knife before it becomes dull.

It is recommended to always do the honing stage after long use of the knife before storing it for next time use.

Using a stone

Traditionally, the whetstone was the only tool that was used to sharpen knives. This manual method of sharpening uses far better control than the use of an electric sharpener. Caution must always be exercised when using this method.

This is because sharpening the wrong way can destroy your knife’s edge. Furthermore, since the blades of fillet knives are very thin, caution must be observed to avoid extra sharp edges.

The attainment of a better and sharp knife is determined by the criteria you use to sharpen this knife.

Therefore, when sharpening your filleting knife by the use of the grinders stone, the following procedure should be used;

  • Gliding the knife-edge through the grinders stone.
  • Position the extremity of the knife a bit over the grinders stone to glide the knife towards to have a searing knife

You can make use of coinage to assist you in positioning your cutter at a 90-degree angle and place your digits over the cutter. Securely slide it over the grinder’s stone protecting your digits from a possible cut. The procedure is done simply on each edge of the knife up until it is sharp as desired.

Use of an Accusharp tool

This method is also simple. The following procedure should be used;

  • Place the knife on a level area with the cutting side facing up.
  • Place the V-shape part of your Accusharp tool on the knife.
  • Begin to glide the tool over to the blade
  • Do the procedure repeatedly to get the sharpness that you require.

Use of a honing steel

This sharpening rod is used to hone the edge of your knife by sliding the knife over the steel. Slide the knife carefully especially if it is your first time using the tool. The following procedure should be followed;

  • Slide the sharp edge of the fillet knife over the honing steel
  • Position the back end of the knife slightly above the honing steel to slide the knife forward and make the knife sharp

Are Boning and Fillet Knife the Same?

Are boning and fillet knife the same

There exists a significant difference between the fillet knife and the boning knife. Boning knives are exclusively used for taking away bones from the meat whereas fillet knives are universally used for removing bones and skin from the meat, particularly fish.

Although, there exists a connection between fillet knives and boning knives because boning knives can be used for filleting if they are versatile.

Below is a table indicating the difference between the two types of knives




Fillet knives Boning knives
Flexibility Flexible Not necessarily flexible
Blade Thickness Thinner Not as thin as a fillet knife
Blade shape Sometimes curved upward Usually, straight
Versatility Used for delicate meat like fish Better for larger and tougher meats such as pork, beef or chicken. Can also be used in fish
Maneuverability Easily maneuverable in removing fish skin due to their thinness Sturdier and thicker for tough meat.

Tips on Maintaining a Fillet Knife

  • Wash and dry your knife after use to prevent rusting
  • Keep your knife away from a dishwasher. This will prevent damages caused by the caustic dishwater soap. Caustic damages the high-carbon stainless steel. It is recommended to hand wash by the use of mild-to-medium strength detergent and towel dry.
  • Dry the knife fully before storage and allow it to air dry completely. This will prevent rusting
  • Store the knife away from other metals such as in a stainless sink or aluminum pan. This is to prevent pitting and rusting. Store it with other knives made from the same metal using a knife roll.
  • Use a scalloped knife for the initial cuts to prevent dullness especially if the fish scales are heavy-duty
  • Wipe the knife with vegetable oils after washing and drying for protection.
  • Use light pressure to sharpen and hone to prevent dullness and damages to the blade


Many cooking enthusiast and beginners don’t know what is a fillet knife and what is used for? But in this guide, I have explained all about it.

I hope now you know all about it and further you can use it properly. Finally, I would like to say, a good quality fishing knife can give you the best performance in any situation if you care it properly.

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