RiverFish

Grayling · Thymallus thymallus

Grayling in the River Onny

Largest measured grayling: 33.4 cm

The largest grayling measured in Environment Agency surveys of the River Onny was 33.4 cm, recorded at Bromfield on 6 August 2021.

Across 288 measured grayling, the median measured length was 10.3 cm.

RiverFish uses Environment Agency survey measurements rather than rod-and-line angling records. These figures show fish measured during EA surveys of the River Onny.

See grayling records across England →

Most recent observation10 September 2025Craven Arms (DS Halford Weir) · 6 fish
Largest measured grayling
33.4 cm
Median length
10.3 cm
Fish measured
288
Survey locations
5

Individual EA measurements

Largest measured grayling

The largest individual measurements in this river and species dataset. Equal measurements are retained as separate surveyed fish.

LengthSurvey dateSurvey locationSurvey ID
33.4 cm6 Aug 2021Bromfield160073
33 cm19 Jun 2014Bromfield141467
31 cm23 Jun 2000Bromfield15667
31 cm23 Jun 2000Bromfield15667
30.5 cm26 Sept 2022Upstream Plowden Mill161496
30.1 cm13 Sept 2022Craven Arms (DS Halford Weir)161403
29.5 cm23 Aug 2022Bromfield161301
29 cm14 Aug 2023Craven Arms (DS Halford Weir)162920
28.9 cm29 Aug 2024Horderley168252
28.9 cm23 Jun 2000Park Farm15664

Lengths are direct survey measurements. RiverFish does not estimate fish weights from length.

Explore the river

Where grayling were found

Each point marks a survey location with at least one grayling record.

Choose a point on the map to see what was recorded there.

Map points are approximate and don’t show fishing access. Check local permissions before visiting.

Place surveyedFirst recordedLast recordedVisits finding grayling
Craven Arms (DS Halford Weir)4 Aug 202110 Sept 20255
Bromfield25 Sept 199129 Aug 20258
Upstream Plowden Mill11 Aug 202120 Aug 20254
Park Farm23 Jun 200016 Sept 20249
Horderley11 Aug 202129 Aug 20243

Choose a point or table row to see the location. More survey visits can mean more records, but not necessarily more fish.

1991–2025

Survey records by year

Each bar shows how many survey visits recorded grayling that year.

Fish measured by surveyors

Measured length distribution

See how the 288 measured fish were spread across different length ranges.

Smallest
6.5 cm
Lower quarter
8.6 cm
Median
10.4 cm
Upper quarter
20.6 cm
Largest
33.4 cm

Lengths are direct survey measurements rather than anglers’ catches.

More fish in this river

Explore the River Onny

Compare other species with enough survey and measurement data for a detailed page.

Bullhead Stone loach Minnow Brown / sea trout Atlantic salmon European eel

Before you fish

Good to know

These are past survey records, so the fish present today may be different. Map points are approximate—check local access, permissions and fishing rules before visiting.

Learn how RiverFish uses the data →