RiverFish

Bullhead · Cottus gobio

Bullhead in the River Colnebrook

Largest measured bullhead: 9.5 cm

The largest bullhead measured in Environment Agency surveys of the River Colnebrook was 9.5 cm, recorded at Thorney Golf Course on 16 October 2001.

Across 42 measured bullhead, the median measured length was 5.5 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 Colnebrook.

See bullhead records across England →

Most recent observation2 June 2026Wraysbury
Largest measured bullhead
9.5 cm
Median length
5.5 cm
Fish measured
42
Survey locations
5

Individual EA measurements

Largest measured bullhead

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

LengthSurvey dateSurvey locationSurvey ID
9.5 cm16 Oct 2001Thorney Golf Course73302
9.2 cm16 Oct 2001Thorney Golf Course73302
9 cm16 Oct 2001Thorney Golf Course73302
9 cm16 Oct 2001Thorney Golf Course73302
8.9 cm16 Oct 2001Thorney Golf Course73302
8.6 cm16 Oct 2001Thorney Golf Course73302
8.5 cm16 Oct 2001Thorney Golf Course73302
7.9 cm16 Oct 2001Thorney Golf Course73302
7.3 cm31 Aug 2005Thorney Golf Course86581
7 cm16 Jul 2004Thorney Golf Course80520

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

Explore the river

Where bullhead were found

Each point marks a survey location with at least one bullhead 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 bullhead
Wraysbury3 Jun 20152 Jun 20269
Thorney Golf Course16 Oct 200120 Jun 202310
Hythe End12 Jun 20086 Jun 20144
Horton Upstream Site24 Apr 201024 Apr 20101
Horton Downstream site23 Apr 201023 Apr 20101

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

2001–2026

Survey records by year

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

Fish measured by surveyors

Measured length distribution

See how the 42 measured fish were spread across different length ranges.

Smallest
1.8 cm
Lower quarter
4.3 cm
Median
5.6 cm
Upper quarter
6.6 cm
Largest
9.5 cm

Lengths are direct survey measurements rather than anglers’ catches.

More fish in this river

Explore the River Colnebrook

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

European eel Perch Roach Chub Pike Gudgeon

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 →