Grass Carp

By Alex Clayton · Updated 23 October 2026

The grass carp (Ctenopharyngodon idella) is a member of the carp family native to eastern Asia, also known as the white amur. In Britain it lives only in waters where it has been stocked, because UK temperatures are thought too low for it to breed successfully.

That single fact shapes grass carp fishing in the UK. Every fish you hook was put there by a fishery or club, and moving one without a permit is an offence.

This guide covers identification, size and the record question, the stocking rules, where and when to fish, baits that suit a weed eater, and handling on the bank.

What Is a Grass Carp?

Why would anyone put a fish into a canal on purpose? Because it eats weed.

The grass carp is a separate species from the common carp (Cyprinus carpio), although both belong to the same family, Cyprinidae. That matters for identification. Mirror and leather carp are scale forms of the common carp, so there is no such thing as a “mirror grass carp”. For how the different fish fit together, see our UK carp species guide.

Grass carp is the usual name in Britain. White amur is another common name for the same fish.

The species first arrived here as a living weed cutter. According to the Canal & River Trust, early introductions for weed control were made to the Lancaster Canal by British Waterways and Liverpool University, and a small population is still there today.

That diet is why they were chosen. Grass carp feed mainly on aquatic vegetation, yet the Trust notes they will take most angling baits, which is what makes them catchable at all (more on that in the bait section below).

Today, most anglers meet grass carp in stocked carp lakes rather than canals.

How to Identify a Grass Carp

That “personal best chub” in your photos might not be a chub. Farnham Angling Society notes that grass carp are often mistaken for a big chub, and a long, fully scaled fish with no barbels can fool you at first glance.

Look for these features. A grass carp is fully scaled and has no barbels. The head is low, flat and broad, with a small terminal mouth that sits at the front of the head and turns slightly upwards. The eyes are small and set low. The scales are large with dark edges, which gives the flanks a net-like pattern, and the body is long and cylindrical, almost torpedo shaped.

Feature	Grass carp	Common carp	Chub
Barbels	None	Two pairs	None
Mouth	Small, terminal	Protrusible, downturned	Large, wide
Head	Low, flat, broad	Deeper, sloping	Broad, blunt
Body	Long torpedo	Deeper, humped back	Long, rounded
Typical UK size	8 to 20lb on average	See the common carp guide	See the chub guide

Barbels are the fastest check against a common carp. Against a chub, look at the mouth: a chub’s is big and wide, a grass carp’s small and neat.

Scale pattern settles any remaining doubt. Mirror carp and leather carp are scale forms of the common carp, with patchy or missing scales. A grass carp is always fully and evenly scaled.

For side-by-side help with other species, use our UK fish identification guide.

If it has barbels, it is not a grass carp.

How Big Do Grass Carp Get in the UK?

There is no official British record grass carp, even though fish of over 50lb have been reported from English lakes.

For what you are likely to catch, Farnham Angling Society puts the UK average at 8 to 20lb (3.6 to 9.1kg). The Canal & River Trust gives a typical length of 60 to 100cm and a general maximum of about 40lb (18kg). Grass carp live for around 10 to 15 years.

They grow slowly here. The Farnham club guide says UK fish put on only about 1 to 3lb a year, far slower than in France or central Europe.

On records, the sources say this:

The Canal & River Trust states that grass carp are not on the British Record (Rod Caught) Fish Committee list.
The largest reported UK grass carp is 57lb 4oz, caught by Kane Hammond from St George’s Lake, Shepperton, as reported by Angling Times on 5 August 2025. It is unofficial.
The previous best reported fish was 56lb 2oz, caught by Alan Cooper from Little Moulsham Lake, Yateley, in 2023. Also unofficial.

These are rare specimens, not what a typical stocked lake holds. Before you claim a record of any kind, check the British Record (Rod Caught) Fish Committee for its current categories.

Why Every UK Grass Carp Was Stocked, and the Rules on Moving Them

Grass carp spawn only when the water is above about 20°C, and UK temperatures are thought too low for successful breeding. Numbers only change through stocking, which is also why fisheries can control them.

If you run a club or a fishery in England, the one document that matters is an Environment Agency live fish movement site permit. Wales is regulated by Natural Resources Wales, and Scotland and Northern Ireland have their own systems, so check with your own authority if you are outside England.

According to GOV.UK guidance on moving live fish:

The Environment Agency regulates the movement of all live fish, fry and eggs to and from rivers, canals, drains and stillwaters.
Introducing fish without a permit or authorisation is an offence. Prosecution and a fine of up to £50,000 are possible.
Permits are free and usually permanent. A decision usually takes up to 25 working days, and a permit covers only the named site, waters and species.
Fish going into a river, canal or conservation-designated stillwater must come from a registered aquaculture production business. A fish health check may be needed for waters connected to open water.

Keeping is a separate question. GOV.UK guidance on non-native fish says grass carp can be kept without an ILFA licence from the Cefas Fish Health Inspectorate in ornamental trade premises, indoor aquariums and private garden ponds of up to an acre with no risk of escape. That exemption covers keeping only. It does not let you stock a fishery.

Contact the Environment Agency fish movements team (fmapplications@environment-agency.gov.uk, 0208 474 5243) or the Fish Health Inspectorate (fhi@cefas.gov.uk, 01305 206 700), and check GOV.UK for the current process before you apply.

For anglers the rule is simpler: never move a caught grass carp to another water.

Where and When to Fish for Grass Carp in the UK

Nothing wastes a session like fishing for a species that isn’t in the lake.

Because grass carp don’t breed here, they are only found where a fishery or club has put them. In practice that means club waters and specialist carp lakes, plus the small population left in the Lancaster Canal. The big reported fish have come from venues such as St George’s Lake at Shepperton and Little Moulsham at Yateley, so check with the fishery before you travel.

Check the venue’s stock list, often on its website, or ask the bailiff. You also need a rod licence to fish in England and Wales, so read our fishing licence guide first.

Farnham Angling Society puts grass carp at their most active from April to October, and general angling guidance points to June to September as usually best. Below about 10°C they are hard to tempt.

Hot, still, bright days bring them up to cruise and bask near the surface, often along the edges of weed beds.

If you want to target them, pick a warm, still day in high summer on a water that lists them.

How to Catch Grass Carp: Baits and Methods That Suit a Weed Eater

A fish that lives on weed will still take a piece of bread.

Grass carp feed mainly on vegetation but will take most angling baits, as the Canal & River Trust points out. The catch is that they spook easily. Club and angling guides agree that the standard carp approach of a bolt rig over a bed of boilies often fails for them.

Surface fishing

Surface fishing in hot, still weather is the main way to target grass carp specifically. Our surface fishing for carp guide covers the general method.

Choose a calm, warm day.
Walk the lake and look for cruising or basking fish.
Free-offer floating bread or dog biscuits a little ahead of the fish.
Once the fish are taking the free offerings confidently, fish a hookbait on a controller float or freeline it.
After the take, let the clutch give line rather than clamping down.

Bottom fishing

When nothing shows on top, Farnham Angling Society suggests a carp-style leger with the bait popped up just off the bottom. Bites are often bream-like, with dropbacks rather than screaming runs, so strike at any steady movement of the indicator.

Bait	Best used	Why it works
Floating bread	Surface, hot still days	Soft and buoyant, easy to free-offer and match on the hook
Dog biscuits	Surface, hot still days	Float well and can be fed steadily to build confidence
Popped-up baits	Bottom, when fish aren’t showing	Sit just off the bottom, above weed and silt

The Canal & River Trust advises strong, durable tackle for these streamlined, weed-dwelling fish. As a typical carp-fishing starting point, use a carp-style rod and a reel with a smooth clutch, with mainline strong enough to steer a powerful fish away from weed.

Best for: warm surface sessions. Skip the heavy boilie bed if grass carp are your target.

Playing and Handling Grass Carp

Set your clutch so it gives line before you hook up. Farnham Angling Society advises letting the clutch give line, which matters with a fish this powerful.

The fight often follows a pattern. Farnham notes that grass carp often follow you in quietly and then fight hard at the net. Keep the net ready, don’t rush them, and steer them away from weed early, because a weed-bed lie strains tackle and risks a snag.

Unhook on a large mat on level grass and keep the fish wet. The long body is hard to hold steady, so keep it low to the ground where a sudden kick does no harm. Our guide to unhooking and handling fish covers the basics in more detail.

Return the fish promptly to the water it came from. As covered in the stocking section above, it must never be moved.

Give line early, keep the fish wet and low, and it will go back in good order.

Frequently asked questions

Are grass carp native to the UK?

No. Grass carp are native to eastern Asia and were introduced to Britain, with early introductions made for weed control in the Lancaster Canal. Today they are found only in waters where they have been stocked, mostly carp lakes and club waters.

Can grass carp breed in the UK?

They are not thought to breed successfully here. Grass carp spawn when the water is above about 20°C, and UK temperatures are thought too low for successful breeding, so every population depends on stocking.

What is the British record grass carp?

There is no official British record category for grass carp. The largest reported UK fish is 57lb 4oz from St George's Lake, Shepperton, reported by Angling Times in August 2025, but it is unofficial. Check the British Record (Rod Caught) Fish Committee for current categories.

Is a white amur the same as a grass carp?

Yes. White amur and grass carp are two names for the same species, Ctenopharyngodon idella. Grass carp is the name usually used in Britain.

Do you need permission to stock grass carp?

In England, yes. A fishery needs an Environment Agency live fish movement site permit that names the species, and stocking without one is an offence carrying a possible fine of up to £50,000. Elsewhere in the UK, check with the relevant authority.