How to pick the best fillet knife for fishing

A fillet knife is a specialty tool for filleting fish. Here is how to choose one that will fit your needs.
by Leon Pantenburg
After a few weeks on the Mississippi River, my gear was pared and refined for lean, efficient cruising. (To read the story of my end-to-end Mississippi River canoe trip, click on Canoe Voyage.) All the extra fishing gear I didn't need was sent home.
The Forschner six-inch boning knife (top) with a flexible blade is a fine tool for filleting fish; the Cutco shown below it has a seven-to-nine inch adjustable blade. (Pantenburg photo)

I carried two knives for the rest of the six-month journey: a Buck folding hunting knife rode in a sheath on my belt and a filleting knife was in my tackle box.
The Buck handled everything from spreading peanut butter to cutting apples to beheading fish.
My fillet knife was a Fisckar with a six-inch blade. It worked very well for filleting pan-sized fish and was used at least once a day to prepare whatever fish I caught.
A good specialty knife makes filleting fish easy. Picking the right one is not that hard.
To start with, a fillet knife is a specialized tool, featuring a flexible, thin blade and it wouldn't be my first choice as an all-around survival knife. The long, thin blade that makes it good for filleting means it won't be the best choice for skinning big game animals. The fillet blade would also not hold up well under prolonged use for whittling, batoning wood or every day cutting chores.
Here's what to look for in a good fillet knife:
Flexible blade: The blade needs to be sharp, but flexible, so it moves easily around bones. But it needs enough backbone, so it can cut through small bones, such as those pesky "Y" bones in northern pike.
Non-slip handle: A smushy, easy-to-grab handle that doesn't get slippery is a really good idea for safety. Once some fish guts or slime get on the knife, you don't want the handle to be hard to hold.
Easy to sharpen:A fillet knife will get used for a lot of cutting, and will have lots of opportunities to get dull. The steel
 

This Mora cleaned this limit of trout and was shaving sharp at the end of the job. The soft, non-slip handle was safe to use, even when covered with slime, scales and fish guts.


needs to hold an edge well, but still be easy to sharpen. While I generally prefer carbon steel because it's easier to sharpen, stainless may be a good choice in a blade that will be constantly exposed to blood, fish scales and water.
Appropriate blade length: Lengths of blade, IMO, should match the size of the fish. A five-inch is about the minimum for smaller panfish, and I like a six-to-seven inch for medium fish, and a nine-inch for steelhead, salmon and larger saltwater fish.
My six-inch Forschner boning knife is a first cousin to a fillet knife, and I use mine a lot for fish filleting. The Forcshner is designed for meat cutting, but the only difference I can see is that the boning blade is a little less flexible than that of a filleting blade.
Like all survival tools, the one that you like best and that you can use most safely, is your best choice!

Before you buy a knife: Check out what kind of steel is in the blade

A well-designed knife with inferior steel in the blade is a waste of money. Worse, it could break or fail when you need it most. Before you buy anything, consider the steel in the blade. Here are some steels in knives I have used and trust.

by Leon Pantenburg
The most important aspect of a survival knife, IMO, is the quality of steel in the blade.
A good blade steel will stay sharp, but be easy to resharpen. It will hold its edge throughout a variety of tasks it may be called upon to do, ranging from cutting rope, whittling sticks, cleaning fish or small game etc. During rough tasks, it won't break, provided reasonable care it taken.
Long before I saw the steel characteristics list below, I had opinions on blade steel. Based on field use and experience I gravitated toward certain knife brands. There are many excellent knives on the market, and I can't test them all. But these have worked well for me, primarily because of the excellent quality blades.
This Mora is an incredibly useful knife in a multitude of tasks. (Pantenburg photo)

Mora: This small, inexpensive knife is a workhorse. One of my hunting buddies got a Mora 840 and started using it. He has other, excellent hunting knives, but so far he has field dressed three deer and an elk with his Mora. He claims he doesn't have to re-sharpen the Mora when working on a carcass. Many Mora-brand blades are UHB-20C carbon steel.
PUMA: One of my favorite small game knives is the PUMA stockman pocket knife. The knife carries easily in a pocket while bird or waterfowl hunting, and the blade designs are just what you need for field dressing small animals. Another nice aspect is that with three blades, you can switch out as soon as one blade starts to get dull.
Here are three of my favorite small games knives, From top: Opinel, a vintage Imperial fish knife, and the Puma stockman. (Pantenburg photo)

The steel used to make PUMA German knives, according to the company brochure, is the "best knife steel in the world." The proper amount of carbon makes a knife easy to sharpen and hold a cutting edge, but it also allows a knife to rust more easily unless other trace elements are added to protect oxidation.
In the 440C steel, about 1% carbon is added for a great edge and about 17% chromium to maintain the temper but inhibit rust, according to PUMA. About 0.35% Silicon is also added to the base alloy to deoxidize the steel and further stabilize the blade. Additionally, other trace elements such as manganese, phosphorus, sulfur, and molybdenum are added to increase the ability of the steel to form an edge and hold it once formed. These trace elements cause the molecules to align more evenly when cooling to give better structural strength and consistency.
 
This Cold Steel SRK has served me well for more than 20 years. (Pantenburg photo)

Cold Steel: My SRK shows wear, but it is still going strong after more than 20 years of constant use. At one point, I field dressed three deer without resharpening it.
I also really like the Master Hunter. A couple years ago, I deliberately used it for all my cutting tasks on an elk hunt. For the finale, the Master Hunter was used to skin a cow elk. During this hunt, the knife was used extensively, and didn't need re-sharpening.
My old SRK has COLD STEEL CARBON V MADE IN USA stamped on the blade, but today's SRK includes steel of VG-1 San Mai IIIAUS 8A.

I bought my Buck folder in 1976, and used it for years before replacing it with a Cold Steel SRK. 

Buck: I bought my first Buck folder new for $25 on August 31, 1976, at the Ace Hardware Store in Lovell, Wyoming. I used it extensively until I opted for a rigid blade and bought my SRK in 1991. That Buck was my everyday carry knife on my six-month, end-t0-end Mississippi River canoe voyage. The blades held a great edge, despite being used for virtually everything a canoe knife can be used for.
Buck’s standard blade material, according to the Buck Company, is 420HC because it combines "excellent wear resistance of high carbon alloys with the corrosion resistance of chromium stainless steels." An exclusive heat-treat process for superior corrosion resistance, the company claims, creates "excellent tensile strength, hardness and wear resistance." 420HC Steel is a High Carbon (HC) version of standard 420 martensitic stainless steels, Buck says, which means they can be can be hardened to a Rockwell hardness of Rc 5.
Boker: Boker is a commercial manufacturer and distributor of knives, based in Solingen, Germany, however they've long had production facilities outside of Germany. The knifes they sell in America are made in Denver, Colorado.

My dad got the classic Canoe pattern Boker for Christmas on year. It went right into his pocket and to work as a farmer/carpenter's knife. The Boker held up extremely well to all the use and abuse. While the blades showed extensive wear from sharpening, there was no potential for failure. Dad lost the knife one fall while we were picking corn.
Boker uses many different materials in its blades, so before you buy, check out the specs.

Here is "the tip of the iceberg" of knife steels, posted by Steven on Linked In.
154 CM: Carbon 1.05 %; Manganese 0.5%; Chromium 14%. A high carbon alloy, a very hard steel, first used for knifes in 1972. Used for combat knives by companies like Gerber and Benchmade.
420: Carbon 0.15%-0.6%; 1% Manganese; 12-14% Chromium. An inexpensive steel, but hard steel.
420HC: Carbon 0.5-0.7%; Manganese 0.35-0.9%; Chromium 13.5%. A popular, hard steel. Used by companies like Gerber and Buck knives.
440A: Carbon 0.60-0.75%; Manganese 1.0%; Chromium 16.0-18.0%. High carbon, hard steel. Used by SOG for their SEAL 2000.
440B: Carbon 0.75-0.95%; Manganese 1.0%; Chromium 16-18%. Used by Randall Knives.
440C: Carbon 0.95 - 1.20%; Manganese 0.40%; Chromium 17.0%; Vanadium 0.50%; Molybdenum 0.50%. One of the most popular knife steels in the world. Hard, durable, and easy to work with. Used in the SOG Bowie knife.
ATS34: Carbon 1.05%; Manganese 0.4%; Chromium 14.0%. A Japanese version of 154 CM, a hard steel that is used by Spyderco, Buck, and Gerber knives.
AUS-8: Carbon 0.7-0.8%; Manganese 1.0%; Chromium 13.0-14.5%; Nickel 0.5%; Vanadium 0.1-0.25%; Molybdenum 0.1 - 0.3%. A hard steel used by many custom knifemakers and companies like Spyderco, SOG, and Kershaw among others.
CPM-S30V (Also called S30V): Carbon 1.45%; Chromium 14%; Molybdenum 2%; Vanadium 4%. A high wear, durable, hard steel, excellent for knives. Used by Spyderco, Lone Wolf, and Benchmade.
CPM440V: Carbon 2.15%; Manganese 0.4%; Chromium 17%; Vanadium 5.5%; Molybdenum 0.4%. An extremely hard, high carbon steel. Used for Kershaw folding knives, like the Ken Onion designed Boa knives.
D-2: Carbon 1.5%; Molybdenum 1%; Chromium 12%Vanadium 1%. A stain-resistant, but not quite stainless, tool steel, used in knife making by Bob Dozier, Benchmade, and Ka-Bar knives. Has good edge retention, but needs to be cleaned frequently so it does not rust.
Damascus Steel: A legendary steel used by Muslim people against Europeans during the Crusades. It was said to be much stronger, flexible, and sharper than European steel. The process for making it was lost. Many people have experimented with recreating Damascus steel, notably Bill Moran.
M-2: Carbon 0.85%; Tungsten 6.35%; Molybdenum 5.0%; Chromium 4.0%; Vanadium 2%. A good steel used in kitchen knives and folding knives. A high-speed steel, meaning it is resistant to high temperatures and will maintain its edge even when extremely hot.
M-4: Carbon 1.3%; Tungsten 6.35%; Molybdenum 5.0%; Chromium 4.0%; Vanadium 4%. Much like M-2 in its heat resistance, but with a higher carbon that makes it more difficult to sharpen or work. Makes an excellent knife blade.
O-1: Carbon .85-1%; Manganese 1-1.4%; Chromium 0.4-0.6%; Vanadium 0.3%. A very popular, easy to tool, high carbon steel. One of the most popular knife steels for beginning knifesmiths.
Sandvic 12C27: Carbon 0.6%; Manganese 0.35%; Chromium 14.0%. A Swedish steel, very popular because it has few impurities.
Stainless steel: A steel that has a high chromium content to prevent rust. Because knives need high carbon to remain sharp, a stainless steel for knives is just rust resistant, not completely rust proof.
Titanium: A lightweight, hard metal used for knife handles and parts. It does not have good edge retention, so it does not typically make good blades. Because of its resilience against harsh elements, it is used frequently for diving knives.