A filet knife is a thin, flexible knife, usually around 6 inches (150 mm) in length. The blade is is usually much more shallow than the tang. These characteristics give the filet knife excellent mobility when being used to filet cuts of meat or fish, allowing it to manoeuvre around bones. This also aids in removing the skin from fish by allowing the user to flex the blade along the countertop. Filet knives are typically kept very sharp in order to minimize the amount of damage the edge does.
It is important that any knives are kept sharp, as blunt knives require more force to use, actually increasing the likelihood of injury (cuts from a sharp knife heal more quickly than those from a blunt one). A knife sharpener can be used to sharpen knives.