Don't ruin that perfectly good fillet—this handy guide shows you how to cut a large piece of fish from the grocery store like a pro.
Dilly Salmon Packets with Asparagus
Credit: Jennifer Causey; Styling: Heather Chadduck Hillegas

You’re cooking salmon for dinner, and the recipe you’re making calls for four skinless 6-ounce fillets. Seems simple enough, but in an attempt to save money, you bought one large piece of salmon instead of individual fillets. Oh—and the skin is still on, too. You try to pull off the skin, but butcher the fillet to the point where you’re better off just tossing it into fish stew.

Fish isn’t cheap—and a mangled mess all over your cutting board is just plain sad. But with some basic knife skills and a little practice, you can easily skin and portion a large piece of fish like a pro in no time. Below find a step-by-step guide, plus helpful tips, for perfectly-portioned fillets. Before you even pick up your knife, keep these three pointers in mind:

  • Always cut the fish before you cook it. Raw fish is already delicate, but hot, cooked fish is even more fragile. If you need portioned fish for a recipe, you’ll get the prettiest, cleanest pieces if you cut it before sauteeing, baking, or grilling it.
  • Use the sharpest knife you own. When skinning or portioning fish, use a knife that can slide through it cleanly and effortlessly. Using a dull knife can end in a torn or roughly cut fillet (which doesn’t look very pretty, either). A basic chef’s knife will get the job done, but if you want to go the extra mile, consider buying a boning knife or fillet knife. These types of knife have a long, flexible blade that’s perfect for making precise cuts.
  • Make long, smooth cuts. We can’t stress this enough—fish is extremely delicate. And whether you’re skinning or portioning a fillet, making long, fluid cuts with your knife is the best way to prevent tearing the flesh. For the best results, use a chef's knife or boning knife (you’ll have a tougher time making clean cuts with a short paring knife or jagged serrated knife).

Step One: Figure out how much fish you need.

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Credit: Photo by Michael Harlan Turkell

Reference the recipe before you hit the grocery store or seafood market, making sure to note the exact number of ounces or pounds of fish that you’ll need total. If you aren’t using a recipe, you can follow this rule of thumb—a standard serving size for fish is about 6 ounces (or about ⅓ pound). So, if you’re grilling salmon for four people, you’d need about 24 ounces or 1 ½ pounds of fish.

Asking your fishmonger for the exact amount prevents you from buying too much fish, or even worse, not enough. However, not all grocery stores, like Trader Joe’s, have a fishmonger—and if you’re limited to large fillets that are pre-packaged, just buy as close to the amount you need as you can. When in doubt, it’s much better to be several ounces over what you need, rather than slightly under.

Step Two: Check for pin bones.

If your fish falls into the round fish category—such as salmon, cod, sea bass, trout, snapper, and sablefish—it contains pin bones, a row of small bones that run along the length of the fillet. While individual fillets often have the pin bones removed already (you’ll know if the fish is labeled “boneless,” and it’s typically more expensive), larger pieces of fish are more likely to have them.

To check for pin bones, lie the fish skin-side down on your cutting board. Next, run your hand along the fillet. You may not see the them, but you’ll definitely be able to feel them. To remove the pin bones, use a pair of sturdy tweezers to carefully pull them out one at a time.

Step Three: Remove the skin.

How to Remove Fish Skin
Credit: Photo: Randy Mayor

We love the crispy texture of pan-seared skin-on fish, but some recipes (especially stewed, baked, or breaded fish) call for skinless fillets. If you buy larger pieces of fish like salmon or flounder, they may still have their skin. So, how do you remove the fish skin without ripping your precious fillet to shreds?

Here’s the best way to skin a fish—and you can use this method for nearly any type of skin-on fish. (Note: While skinning a fish fillet is excellent knife skills practice, some fishmongers may also remove it for you if you ask.)

  1. Place the entire fillet on your cutting board skin-side down.
  2. Hold the tail end of the fillet and make a cut between the flesh and skin.
  3. Angle the knife toward the skin. Securing the skin with your other hand, make a smooth sawing motion with your knife, keeping it as straight as possible.
  4. Take your time, and don’t fret if you end up leaving some of the flesh on the skin—practice makes perfect!

What should do you with the skin after it’s removed? You can discard it, or save it to make crispy fritters or to flavor fish stock.

Step Four: Portion the fish.

How to Portion Fish
Credit: Oxmoor House

Oxmoor House

Now, once the skin is off, you’re ready to portion the fillet into individual pieces. Here's an easy way to do it:

  1. Place the fillet skin-side down (or the side that used to contain the skin) on your cutting board. Make sure the fillet is facing horizontal to you.
  2. Make crosswise cuts from one side of the fillet to the other so that you have the exact number of pieces you need for your recipe. For example, if you bought 24 ounces of fish for a recipe that serves four, cut the fillet into four pieces.

Here’s the one caveat to this method—because big fillets are rarely the same thickness throughout, dividing it into equal-sized pieces won’t always work. The closer you get to the belly of the fish, the thicker the fillet. On the other hand, the closer you are to the tail of the fish, the thinner the fillet. Account for this by cutting the pieces closest to the tail slightly larger than the ones closest to the belly.

How to Portion Pre Packaged Fish Fillets
Credit: Oxmoor House

Oxmoor House

Lastly, if you're using a pre-packaged fillet, and it’s slightly over the amount you need, use your best judgement. For instance, if you bought just under a pound of fish, but you’re making a recipe that calls for two 6-ounce pieces, it’s much easier to just cut the fillet in half. Don’t sweat the extra ounces, and just eat what you can. Besides, you can always save the leftovers.

Step Five: Cook it!

This is the best—and tastiest—part. Follow the cooking instructions in the recipe you’re making, and enjoy your perfectly-portioned fish.