Boning and filleting involve removing pieces of meat from the bones that hold them together.  Most boning knives have a narrow, pointed tip for working around bones and have a slightly stiff blade so that you always know where the tip is.  Fillet knives are usually slightly flexible for working with delicate fish.  They have a narrow blade so that there is as little drag as possible when slicing the fish.  The size of your fillet knife should be proportional to the size of the fish you are working with.  Small fish such as panfish, small trout, and small catfish can be prepared with a 6" knife while large fish such as salmon, tuna, and halibut will need a longer blade.

The Japanese-style Yanagiba is a stiff fillet knife which is used mostly for slicing boneless fillets into bite-size pieces but is also used by the chef to break down the whole fish.  The thick, stiff blade is useful for cutting through the pin bones and rib bones of small to medium size fish.  Please see our section on Sushi/Sashimi knives to see the Yanagibas.