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Types of Carp in the UK

By Alex Clayton · Updated 24 October 2026

UK anglers meet seven named types of carp: common, mirror, leather, ghost, crucian, grass and F1. Four of them (common, mirror, leather and ghost) are one species, Cyprinus carpio, separated only by scale cover and colour.

The other three are genuinely different fish. The crucian is its own species, Carassius carassius. The grass carp belongs to a different genus, Ctenopharyngodon idella. The F1 is a hybrid bred from a common and a crucian.

So the list of carp varieties on a fishery board is shorter than it looks. Below you’ll find how to tell the different types of carp in the UK apart on the bank, which one carries legal rules, and which guide to read next. This page sits within our wider guide to UK fish species.

A mirror and a common carp are the same fish, yet a crucian is a different species altogether. Carp names describe two different things: some name a scale pattern or colour, others a separate animal.

Three groups clear up the confusion:

  • Cyprinus carpio varieties: common (fully scaled), mirror (scattered scales), leather (almost scaleless) and ghost (a colour form linked to koi breeding). Scale cover and colour differ. The species does not.
  • Separate species: the crucian carp, Carassius carassius, and the grass carp, Ctenopharyngodon idella, an East Asian fish stocked for weed control.
  • Hybrid: the F1, a cross between common and crucian carp, bred for commercial fisheries.

Some pages claim leathers are “genetically different” from mirrors. That is true only in the sense that scale cover is inherited. Both are still Cyprinus carpio.

None of the four Cyprinus carpio varieties is native to the UK. A 2017 paper in Ecology and Evolution identifies the common carp as the earliest known live fish introduction to the UK, brought to south-east England by monks in the 15th century. The authors add that an earlier arrival cannot be ruled out (Sayer et al. 2017).

One species in four outfits, two separate species and one bred cross: the table below turns that into a bankside check.

How to Identify Carp: Quick ID Table

Look at the mouth first. It rules out two of the seven types of carp before you count a single scale.

Type Barbels Scales Body shape Colour Guide
Common carp Yes Even, full cover Long, rounded Grey-bronze Common carp
Mirror carp Yes Scattered, uneven sizes As common As common Mirror carp
Leather carp Yes Almost none As common As common Leather carp
Ghost carp Yes Common-style or mirror-style As common Pale, metallic or patchy Ghost carp
Crucian carp None Full Deep, rounded, small fish Rounded reddish fins Crucian carp
F1 carp Varies, see the F1 guide Full Varies, see the F1 guide Varies F1 carp
Grass carp None Full Long torpedo, flat broad head Silver Grass carp

Every Cyprinus carpio variety has barbels at the corners of the mouth. Sources disagree on how many to count, so use “barbels present” as the test rather than a number.

Work through four checks in order:

  1. Barbels. Present means a Cyprinus carpio variety (or possibly an F1). None points to a crucian or a grass carp.
  2. Body shape. A long torpedo with a flat, broad head is a grass carp. A deep, rounded, small fish points to a crucian, though F1s can look similar.
  3. Scale cover. Full and even is a common. Scattered and uneven is a mirror. Almost none is a leather.
  4. Colour. Pale, metallic or patchy markings on a fish with barbels suggest a ghost.

Be honest with yourself at step 2. Crucians, F1s and goldfish crosses are the hardest ID call among the carp types, and the crucian section below explains why.

When you log a catch, record the variety separately. “Carp” tells you far less about a water than “linear mirror”.

Common, Mirror and Leather Carp: Reading the Scales

The fish on the mat has a few scales near the tail and a couple by the dorsal fin. Your mate says mirror. You say leather. You are arguing about one species, because scale cover is the only thing that separates these three types of carp.

Common carp

A common carp carries regular, even scales over the whole body, row after row of near-identical size. The common carp guide covers it in full.

Mirror carp

Mirror carp have irregular, scattered scales, and the category is wider than the name suggests. A linear mirror carries a line of scales along the lateral line. A fully scaled mirror is covered in scales, but they come in mixed sizes, which is how you tell it from a common. The mirror carp guide covers every pattern in between.

Leather carp

Leather carp are practically scaleless. A common angling rule of thumb says a fish with four or fewer scales is a leather, and anything more is a sparsely scaled mirror. Treat that as bankside convention, not an official standard. The leather carp guide has more.

The British Record Fish Committee’s June 2024 coarse list records its carp entry as a mirror, with no separate common or leather categories. Carp records have been reported as changing, so check the current BRFC list on the Angling Trust site before you quote one.

Quick comparison: if a fully scaled fish has uneven scale sizes or gaps in the rows, it is a mirror, not a common.

Ghost Carp: A Colour Form, Not a Species

A pale, almost white fish cruising just under the surface looks nothing like a common carp. It is the same species.

Ghost carp are usually described as a colour form produced by crossing koi with common or mirror carp. The precise origin is not settled, so treat confident origin stories with caution. On the bank, a ghost is Cyprinus carpio and should be identified and handled like any other carp.

The scale pattern can follow either parent, so you will see common-style and mirror-style ghosts. The colour is pale, metallic or patchy. They still have barbels, which separates them at a glance from a silver grass carp.

Koi are ornamental Cyprinus carpio too, not a sub-species, whatever some pages claim. The ghost carp guide goes into the forms in more detail.

Direct recommendation: if you are unsure whether a pale fish is a ghost or a grass carp, check the mouth and the head. Barbels and a rounded head mean ghost.

Crucian Carp and F1s: The Small Carp of the Commercials

In a study of 21 British crucian carp populations, only 62% held exclusively pure crucians. Goldfish were the main hybrid partner, and crosses involving common carp were rarer (Hänfling et al., University of Hull and Environment Agency research). It is one study, not a national figure, but it shows why so many “crucians” deserve a second look.

Crucian carp

The crucian is a separate species, Carassius carassius. Look for a deep, rounded body, no barbels, rounded reddish fins and a small overall size. The BRFC list carries a separate crucian record, so check the current list if you want the figure. The crucian carp guide covers ID and methods in full.

F1 carp

The F1 is a hybrid of common and crucian carp, bred for commercial fisheries and stocked for sport. F1s are usually modest in size, and they are the small carp many anglers meet on commercial lakes. The F1 carp guide explains how they differ from both parents.

Why it matters

A “crucian” with barbels is not a pure crucian. The lookalikes include F1s and goldfish crosses, and some fish sit so close to the line that nobody can name them with certainty on the bank. Check barbels first, then body depth, and accept that a few fish will stay a best guess.

Best for / skip if: crucians suit anglers who enjoy delicate float fishing for small fish. F1s are the fish to expect on many commercial lakes, so skip the crucian hunt if you want a busier session.

Grass Carp: The Odd One Out, and the Rules

A long, silver torpedo runs like a common carp, but there are no barbels and the head is flat and broad. That is a grass carp, and it is the one type of carp where the law matters as much as the ID.

The grass carp, Ctenopharyngodon idella, comes from East Asia and is stocked in lakes to control weed. Look for a torpedo body, a flat head and no barbels. The grass carp guide covers how fisheries manage them.

The Environment Agency says grass carp feeding habits can upset a water’s ecology (Environment Agency). In England, GOV.UK states it is an offence to introduce or keep controlled non-native fish without a licence. No licence is needed for grass carp kept in ornamental premises, aquariums or garden ponds where there is no risk of escape (GOV.UK).

That is the England position. In Wales, Scotland or Northern Ireland, check with Natural Resources Wales, the Scottish Government or DAERA.

Never move fish between waters. Stocking is the fishery’s job.

The verdict: catch it, return it as the fishery asks, and move nothing.

Frequently asked questions

Are mirror and leather carp different species?

No. Mirror and leather carp are both Cyprinus carpio, the same species as the common carp. The only difference is scale cover: mirrors have scattered scales, leathers are almost scaleless. Claims that leathers are "genetically distinct" refer to the inherited scale pattern, not a separate species. See Common, Mirror and Leather Carp: Reading the Scales above.

Is the common carp native to the UK?

No. The common carp was introduced. Current evidence points to monks bringing it to south-east England in the 15th century, making it the earliest known live fish introduction to the UK, though an earlier arrival cannot be ruled out. It is now naturalised.

What is the British record carp?

The British Record Fish Committee, administered through the Angling Trust, keeps the official list. Carp claims are tightly scrutinised because, as Angling Times reported, the committee considers carp uniquely subject to management aimed at producing ever-larger fish. The record has been reported as changing, so check the current list rather than relying on the June 2024 edition.

Can I keep grass carp in a pond?

In England, yes, in a garden pond where there is no risk of escape. GOV.UK says no licence is needed in that case, or for aquariums and ornamental premises. Introducing grass carp anywhere else needs permission. Elsewhere in the UK, check with Natural Resources Wales, the Scottish Government or DAERA.

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