In England and Wales, they can be fished for throughout the coarse fishing season (16 June to 14 March), providing thrilling sport on the fly when the trout season is closed. There is no closed season for grayling in Scotland; where they have been introduced. There are no grayling in Ireland. Well-known grayling flies include the grayling witch, klinkhamers, various nymphs and 'red tags', along with other trout patterns. Flies tied to resemble small pink shrimps have also been found to be useful. A method known as 'Czech-nymphing' has been known to be helpful to anglers where grayling shoal up in colder periods. The method involves moving a series of Czech nymphs under the tip of the fly rod with the flow of the river and the nymphs should entice the grayling to take one. Fly-anglers may wade in the river to perform this method where they can access deeper water. Wading does not necessarily spook the grayling as they are generally less cautious than trout and are not as easily put off by human presence.