Fillet knife sizes are measured by the blade. On the average, they are between four to nine inches long. The most widely used are 6, 7 and 8 inch knives.
This will depend on what fish you are working on. Larger fish will require a bigger blade. This will be necessary due to the fish’s extra surface and girth. A shorter blade is necessary for smaller fish so it will be easier to handle.
If you are going to work with panfish (crappie, perch and bluegills), a 6 inch fillet knife size will be just right. If you have to cut up small trout or bass, a 7.5 inch blade will suffice.
For big fish like salmon and pike, a 9 inch blade will be needed.
The 7.5 blade is considered the general all-purpose knife. With this you can cut up small and big fish adequately. This size allows you to cut fish with little effort. Ideally you should have two knives of different sizes. But if you can only get one, the 7.5 inch blade should be it.
The standard choice is stainless steel. But not all stainless steel knives are built the same way. The problem is that manufacturers rarely say what kind of steel they use.
The best way to go around this is by buying from a well known company. You can be sure that the quality of the blade is high. Never settle for a cheap, poorly made blade.
Flexing can be important when it comes to slicing and cutting. As a rule, flexing depends on the blade thickness. If the blade is not very thick, it will hold more flex.
The reverse is also true. A short blade ought to have more flex. This is required because small fish need sharper cuts and tight angles. Large blades do not require a lot of flex. The 4 and 6 inch blades have to be flexible and thin.
If you have to clean a lot of fish, the electric fillet knife should be considered. They take a while to learn and are more expensive. But they will save you a lot of time. If you eat a lot of fish, this will be a worthy investment.
The fillet knife size must always be considered before you make a purchase. As the facts above indicate, the dimensions you choose can make a big difference.