The Grayling is a species of freshwater fish in the salmon family (family Salmonidae) of order Salmoniformes. It is the type species of its genus. Despite being a salmonid the Grayling does not share the same spawning time as other species within this group. Whereas Salmon and Trout spawn in the winter months, the Grayling does not spawn until mid to late April.
The Grayling grows to a maximum recorded length of 60 cm (24 in) and a maximum recorded weight of 6.7 kg (15 lb). Of typical Thymallus appearance, the Grayling proper is distinguished from the similar Arctic Grayling by the presence of 5–8 dorsal and 3–4 anal spines, which are absent in the other species; also has a smaller number of soft rays in these fins. Individuals of the species have been recorded as reaching an age of 14 years. Grayling with their huge dorsal fin are unmistakable from other fish. The Grayling is a streamlined fish with a small pointed head, silvery blue body with thin silver / violet stripes and irregular dark spots on the flanks. Grayling are a shoaling fish sensitive to pollution and are generally found in clean, fast flowing, well oxygenated streams and small rivers with gravel or chalk beds.
The Grayling is known as the 'lady of the stream'. They used to be persecuted by anglers for the false perception that they stopped Trout colonising stretches of rivers and streams. However, research has shown that Grayling and Trout feed on different prey items and generally prefer different microhabitats within rivers and streams. Fly fishing tackle for Grayling doesn’t need to be overly heavy because the fish themselves are not too big, so a #5 outfit is usually perfectly sufficient. Dry fly fishing for grayling is an excellent method for catching them.
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. Well-known Grayling flies include: the grayling witch, klinkhamers, czech nymphs and 'red tags', along with other Trout patterns. Flies tied to resemble small pink shrimps have also been found to be useful.
Native to the Palearctic ecozone, the Grayling is widespread throughout northern Europe, from the United Kingdom and France to the Ural Mountains in Russia. While it was introduced to Morocco in 1948, it does not appear to have become established there.