How to fillet a fish with a fillet knife

If you’re new to cooking, filleting a fish can be a bit unnerving. But have no fear, because we’ve put this post together for you with all the info you need about filleting a fish. If that wasn't enough, we also included an easy to follow photo tutorial!

So what do you mean by "filleting"? Well in the culinary sense of the word, it means removing the bones from a cooked or uncooked fish. This can be done either by slicing through the flesh down either side of each bone and pulling them out (the bones will stay inside your skin). 

If you prefer to do the job yourself with a fillet knife, it's not so bad (and honestly, it's a great way to become better at filleting since you're required to dissect each piece into a certain portion of meat).

If you're feeling lazy and would rather use a utensil, then filleting is pretty easy. You can use an "ox-gut or suction" device that hooks up to a kitchen sink. If you don't have one of these handy, there are also fish filleters that are already inserted into the back of forks and cool knives for ease of use (this also makes for extremely clean cuts!).

Cleaning of Fish

Here is what you need for cleaning of fish:

  • Fresh water (enough to cover the fish in a large bowl)
  • 1 tablespoon of baking soda
  • 1 tablespoon of dish soap, like Dawn or Joy
  • A large bowl for the fish to soak in
  • Paper towel and a scrub brush to wash the fish.

  • Step 1 

Place a clean paper towel on the outside of your sink and place your scrub brush next to it.   

  • Step 2

Fill a large bowl with cold water and add one tablespoon each of baking soda and dish soap. Wait for enough bubbles before placing your dirty fish into the soapy water. Make sure that all parts are thoroughly covered.

  • Step 3

Place your fish into the soapy water and wait until the bubbles stop.

  • Step 4

Lift the fish out of the water and place it on the paper towel.   

  • Step 5 

Using the scrub brush, scrub the underside of your fish to remove dirt and feathers.

  • Step 6

Drain out any extra water from your bowl, adding freshwater to replace what you took out. Wash your fish thoroughly in cold water and place it back into fresh cold water for about an hour to kill bacteria.  

  • Step 7

Rinse your fish under running water for about halfway through this time period before putting it back into warm fresh water for about 30 minutes (this is optional).  

Fillet Your Fish: Step By Step

We'll teach you how to clean and fillet a fish using a fillet knife with clear, easy-to-follow instructions for various types of fish. For some larger types of fish, like bluefin tuna and swordfish, we recommend using a sharp knife. It can be helpful to use long work gloves to protect your hands while cleaning the fish. 

  • We don't recommend using plastic bags to fillet fish, because they can cut into the flesh of the fish and make filleting more difficult. For filleting larger species of fish, we recommend that you bring along a sturdy work glove or an old t-shirt to protect your hands while you're working with a sharp knife.
  • When cutting up larger fish like tuna, swordfish and marlin, we recommend using two knives: one fillet knife for bone removal, which we call "cleaning" and one for when cutting up scaled fish like this octopus (for instance), we suggest wearing disposable gloves. This way it won't get in your hands.
  • Before you begin filleting, wash your hands with dish soap and warm water. Make sure the sink or tub is big enough to hold your fish once it's cleaned. We recommend a stainless steel sink because it's easy to clean and won't rust. 
  • You can also use disposable gloves so that it doesn't get in your hands, but if you don't have any on hand, don't worry! You can also just wash with warm water and some dish soap between each step of filleting.

Filleting a fish

On to Filleting!

Manual meat removal is what we call the method of removing flesh from your fish. Manual meat removal is where you remove the flesh off your fish yourself, by hand. This usually sounds to you like a lot of work and work that you don't want to do... but in reality, it's a lot easier than most people think! 

You can remove the flesh quickly and easily with just your hands, some fillet knife skills and a sharp knife. Manual meat removal is especially good for small fish like catfish or tilapia.

To start with, the objective of filleting is to remove the meat from the bones. You want to create boneless fillets without any scales or bones. We are going to assume that our fillet has already been gutted and scaled before coming into contact with us as an angler or fishmonger (if you havent you can do it now). 

In order for this process of fillet fish to go smoothly it is important to have sharp knives and a cutting board. The cutting board will also be important as a place to work. You will also need to have a sharp, sturdy pair of needle nose pliers and a good scale with your fillet knife.

  • Removing the Head and Fins

Start by removing the head, tail and fins of the fish. The head has many pin bones in it that you want to remove. This can be done with the needle nose pliers by pinching the bones until they break off. The easiest way is to fillet a fish from behind, this allows you more room to manoeuvre under the rib cage which is where most of the bones are located especially if you are just starting out.

  • Locate the Lateral Line

This is a series of bones that run from head to tail and are slightly off centre. The lateral line is where the fillet comes from. This is one of the hardest parts of filleting, so be careful and be patient.

  • Insert your Sharp

Sturdy fillet knife into the space between the fourth and fifth rib on the right side. You are going to wedge your knife with a heavy pressure between two of these bones until it cuts through them completely. The trick here is not to cut too high on your first cut, you want to stop just short of severing the ribs themselves. If you do, they will crush against your knife and break it.

  • Cut Through the Ribs

You will want to go through them all except for the last one. The last rib is a little harder because it is attached to a very thin muscle that you don't want cut. Start in back and get your knife between two ribs and cut downward to sever the rib completely, then follow with a cut to a bone on the next rib that is just below it. 

Eventually you will reach the end of your fillet fish, noticing that it has a large, muscular belly (the ventrum). You can stop at this point or continue going down into it.

Fillet knife

Special Knife for Filleting Fish

You should use a special fillet knife for filleting fish. The knife is designed with a long, thin blade attached to a flexible shaft which allows you to easily cut away the bone, sinew, and other excess flesh to create perfect slices of raw meat. These specialty knives are different from the traditional skinning knife which is used for skinning.

A good fillet knife can be used on all types of fish including tuna, mackerel or trout. They come in different varieties including folding and fixed lengths but most commonly have serrated edges that hold their shape well when pulled through hard tissue like fish scales or thick sinewy muscles.

The body of a knife is almost always made of stainless steel. The blade must be strong and sturdy. The steel strength determines how sharp the knife actually is. To get the best results, try to find a knife with a 2 inch, 6 inch or 8 inch blade length depending on the thickness of your cuts and the type of fish you're filleting.

You should also consider buying an essential tool for every kitchen: a shark. The professional cool pocket knives also come in handy for slicing fish into thin pieces as well as for knifing through hard flesh like tuna or mackerel.