Gill rakers are appendages projecting from the anterior edges (the front) of the gill arches.
They aid in the fish's feeding.
The shape and number give an indication of the diet of the fish. Fishes that eat large prey have short, widely spaced gill rakers. This type of gill raker helps prevent the prey item from escaping between the gills.
Fishes which eat smaller prey have longer, thinner and more numerous gill rakers. Species which feed on plankton and other tiny suspended matter have the longest, thinnest and most numerous gill rakers (view the gill rakers of a Basking Shark).
Copyright © Australian Museum, 2006