A gill net is designed to catch fish of a specified type by the use of webbing of a specific size. It looks similar to a trammel net, but has just one wall of webbing. Fish can swim into the net but not through it, because its gills become trapped in the webbing. Gill nets are used to catch catfish, carp, and other species. The net can be set to float or sink (lie high in the water or near the bottom) or drift with the current.