Removing fillets from fish. The long, thin, flexible blade follows the ribcage and the spine, separating flesh from bone in one continuous pass with minimal waste. The flex is the defining feature, and it is what makes the knife specialized rather than general-purpose.
Fish bones are curved and a rigid blade cuts straight, so a rigid blade either leaves flesh on the frame or cuts into it. A flexible blade bends against the ribs and follows them, which is the entire technique.
More flex suits larger, softer-fleshed fish; less flex suits firm fish and gives more control.
Six to seven inches covers most freshwater and inshore fish. Steel should prioritize corrosion resistance: Nitro-V is particularly suited because it pairs pitting resistance with high toughness, which matters in a thin blade.
Rinse and dry after every trip regardless of steel. See cleaning saltwater residue.
Anything requiring force. A flexible blade twists under load and the thin stock will take a set or snap. See using a fillet knife for other jobs.
Our Fishing category is built around exactly this kind of blade.