Grayling

By Alex Clayton · Updated 23 October 2026

It carries an adipose fin like a trout, yet most English rivers treat it under the coarse close season. That is the grayling fish (Thymallus thymallus), a salmonid of clean, fast-flowing rivers, recognised at a glance by its tall, sail-like dorsal fin. Anglers call it the lady of the stream.

Grayling spawn in spring rather than autumn, so they give you river fishing long after the brown trout season closes, as the Wild Trout Trust points out. This guide to one of the most distinctive game fish species in the UK covers how to identify a grayling, where they live, how they behave through the year, the reported British record and the rules in England, Wales and Scotland.

How to Identify a Grayling

Look at the back first. No other UK river fish carries a dorsal fin like a grayling’s, and once you have seen one you will not mistake it. Four features confirm it:

Sail-like dorsal fin. Tall, long and many-rayed. It is larger and often redder in males, which helps you tell the sexes apart.
Adipose fin. A small, fleshy fin between the dorsal and the tail, the mark of the salmon family.
Underslung mouth. Small and set under the snout, built for picking food off the riverbed.
Large scales. Big, clearly visible scales over a pewter or silvery body.

All four are described by the Wild Trout Trust. There is one more test if you have the fish in your hands. A fresh grayling fish is said to smell faintly of thyme, which is where the Latin name Thymallus comes from, according to the Forth Rivers Trust.

The adipose fin causes plenty of confusion, because a trout or salmon carries the same fin. Grayling are salmonids, but they are not trout. They sit in their own subfamily, Thymallinae, alongside the trout and salmon branches of the family rather than inside them.

If the fish has an adipose fin and a sail on its back, it is a grayling. For other silver river fish that can catch you out, use the UK freshwater fish identification guide.

Grayling vs Brown Trout: The Key Differences

On a mixed beat in October you can catch both species in the same session, sometimes from the same pool. A quick glance in the landing net is not always enough. This side-by-side check settles it:

Feature	Grayling	Brown trout
Dorsal fin	Tall, sail-like, many rays	Short and rounded
Mouth	Small and underslung	Larger, at the front of the head, with teeth
Scales	Large and clearly visible	Small, hard to see
Body colour	Pewter to silver	Brown to olive, with dark and often red spots
Where in the pool	Pool tails, slower and deeper water, shoaling in open water	Pool heads, faster current, close to cover
Spawning	Spring	Autumn and winter

The row that pays off when you are reading water is position in the pool. The Wild Trout Trust notes that grayling favour the tails and slower, deeper water and tend to shoal in the open, while trout hold at the heads in faster current near marginal cover. If you have been catching trout at the head of a run, move down to the tail.

Both fish are salmonids with an adipose fin, so that fin alone will not separate them. Go by the dorsal fin and the mouth. For the silver, sea-going form of the brown trout on the same rivers, see the sea trout guide.

Where Grayling Live in the UK: Native and Introduced Rivers

Every grayling in Scotland descends from introductions. The first went into the Clyde from Derbyshire in 1855, according to the Grayling Society, and there are no native Scottish fish.

South of the border the picture is older. The Game and Wildlife Conservation Trust (GWCT) says grayling are thought to be native to the Yorkshire Ouse, Trent, Hampshire Avon, Severn, Wye, Thames, Ribble and Welsh Dee systems. They have been moved widely around the UK since, so a river holding grayling today was not necessarily a native water.

Nation	Status	Example rivers
England	Native to several systems, widely introduced elsewhere	Test, Dorset Frome, Dove, Wharfe, Severn, Calder
Wales	Native in the Wye and Dee, introduced elsewhere	Wye, Irfon, Dee, plus introduced stocks in the Taff, Rhymney, Ewenny and Ogmore and a small Teifi population
Scotland	Introduced only	Tweed and Teviot, Clyde, Annan, Tay, Nith

Welsh river grayling average 30 to 35cm, according to Fishing Wales. Grayling are absent from Northern Ireland and the Republic of Ireland.

Stocking is the main worry for grayling UK populations. The Wild Trout Trust warns that introducing fish from other sources risks diluting the native strains that remain. Most good grayling water is controlled by clubs, estates and associations and fished by permit or ticket, so check with the fishery before you travel.

Habitat, Diet and Behaviour Through the Year

Why do anglers say a river with grayling in it is a healthy river? Because grayling are more sensitive to pollution and rising water temperature than trout or salmon, according to the GWCT.

Habitat. Grayling like steady water moving at about walking pace, typically two to five feet (roughly 0.6 to 1.5m) deep. Pool tails and slightly slower, deeper runs are the classic spots.

Diet. That underslung mouth is built for bottom feeding. Grayling eat aquatic insects, freshwater shrimp, midge and caddis larvae, worms and leeches, and in winter they may take salmon and trout eggs, according to the Forth Rivers Trust. They also rise to surface flies.

Spawning. Grayling spawn in spring, roughly March to May, according to the Canal & River Trust and the GWCT. The Forth Rivers Trust gives April and May, so timing varies from river to river. Leave known spawning gravels alone at that time of year.

Autumn and winter. As the water cools, grayling gather in larger shoals. On the Wye, the Wye and Usk Foundation rates September to December as probably the best period, as reported by Fishing Passport. Grayling feed by sight, so a river running heavy and coloured after rain is a poor time to try.

Conservation. Grayling were once culled as vermin on some southern trout rivers. The GWCT and Wild Trout Trust no longer support culling. The species is listed as Least Concern by the IUCN and as a species of Community interest under the EU Habitats Directive.

Autumn is when the lady of the stream comes into her own.

Grayling Size, Lifespan and the British Record

A 2lb grayling is a good fish on most rivers, yet the reported British record is more than double that.

Typical size: about 30cm, and rarely over 2lb (0.9kg), according to the Canal & River Trust. The Wild Trout Trust puts the largest fish at around 2kg.
Lifespan: 8 to 14 years, according to the Canal & River Trust.
Reported British record: 4lb 8oz (2.04kg), caught by Simon Ellis from the River Frome near Puddletown, Dorset, on 19 February 2019.

Ratification of that fish could not be confirmed when this page was written. Check the British Record (Rod Caught) Fish Committee list for the current record, and see the British fishing records guide for how the system works.

Size also decides whether you can keep a fish. On rivers in England and Wales only grayling of 30 to 38cm can be taken, as the rules section below explains.

Grayling Fishing Rules in England, Wales and Scotland

Search for the grayling season and you will see “16 June to 14 March” quoted almost everywhere. England’s national byelaw does not name grayling in its close season wording.

Rule	England	Wales	Scotland
Licence	Rod licence needed from age 13	Rod licence needed from age 13	No recreational fishing licence, but you need a permit or written permission from the rights owner
River season	Coarse close season on rivers: 15 March to 15 June inclusive; most rivers apply it to grayling	Coarse open season on rivers: 16 June to 14 March (grayling not named)	No closed season for grayling, but avoid the spring spawning months
Daily limit on rivers	2 grayling of 30 to 38cm, measured from snout tip to fork of tail	2 grayling of 30 to 38cm; fisheries can set stricter limits	Set by the fishery or club

Sources: GOV.UK byelaws, catch limits, Natural Resources Wales limits, seasons, Scottish Government, Grayling Society.

The close season question. GOV.UK puts grayling in the coarse catch limits, and the Environment Agency’s close season blog lists grayling among the early spring spawners it protects. Treat grayling under the coarse close season on rivers unless the local byelaw and the fishery say otherwise. See the fishing seasons guide and the fishing licence guide for the detail. Check the current licence price on GOV.UK before you buy.

Club and fishery rules sit on top. The Wye and Usk Foundation runs grayling fishing from 16 June to 14 March, keeps some beats fly only during the trout season and allows maggot trotting from October to March on others. Some beats let you keep grayling within the limits; many fisheries are catch and release only. In Scotland clubs set their own dates, and on the Tay the advice is to avoid April and May.

Northern Ireland. Grayling are absent, according to the GWCT and Wild Trout Trust.

If you are fishing a new river, check the byelaw, then the ticket or club rules, before you travel.

How Grayling Are Fished, and How to Handle Them

Keep the fish in the net, in the water, and most handling problems disappear.

Grayling are caught on nymphs, dry flies, maggot or worm trotted under a float, and small lures where the fishery allows them. The full method guide, with tackle and tactics, is in how to catch grayling.

Grayling twist hard once they are out of the water, which is why they are nicknamed twisters. These points are summarised from advice by Dom Garnett on fisheries.co.uk:

Leave the fish in the landing net, in the water, while you unhook it.
Wet your hands first, and cradle rather than squeeze.
Take a photo in the wet net instead of a grip-and-grin shot.
Release it into steady water and let it swim off in its own time.

Frequently asked questions

Is grayling a coarse or game fish?

Grayling are salmonids, and the Canal & River Trust calls them a game fish. In England, though, the byelaws set grayling catch limits within the coarse fish rules, and most rivers treat them under the coarse close season. Check the local byelaw and the fishery's rules.

Can you keep grayling in the UK?

On rivers in England and Wales you can keep up to 2 grayling a day of 30 to 38cm, unless the fishery sets stricter rules. Many fisheries are catch and release only. In Scotland, the fishery or club sets the limits. See the rules section on this page.

Do you need a licence to fish for grayling?

Yes in England and Wales, from age 13. Scotland has no recreational fishing licence, but you must have a permit or written permission from whoever owns the fishing rights. Where a protection order applies, fishing without that permission is an offence.

Are grayling a type of trout?

No. Both are salmonids with an adipose fin, but grayling belong to their own subfamily, Thymallinae. The tall, sail-like dorsal fin is the quickest way to tell them apart.

Are there grayling in Northern Ireland?

No. Grayling are absent from Northern Ireland and from the Republic of Ireland, according to the GWCT and the Wild Trout Trust.