Gill rakers
Bony or comb-like points on the inside of the gill arches that keep food in and, in filter feeders, strain plankton.
Gill rakers project forwards from each gill arch, on the side facing the mouth. They stop food from escaping through the gills and protect the soft filaments. Their number and spacing match the diet. Fish that eat other fish have a few short, widely spaced rakers. Filter feeders such as the silver carp, sardines, anchovies, the whale shark and manta rays have long, close-set rakers that sieve tiny plankton from the water. Counting gill rakers is a standard way to separate similar species.