RiverFish

Bullhead · Cottus gobio

Bullhead in the River Medway

Largest measured bullhead: 12.7 cm

The largest bullhead measured in Environment Agency surveys of the River Medway was 12.7 cm, recorded at Hartfield on 15 October 2024.

Across 877 measured bullhead, the median measured length was 6.5 cm.

Surveyors recorded weights for 25 bullhead. The median was 0.4 oz (0.01 kg) and the largest recorded weight was 2.5 oz (0.072 kg).

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

See bullhead records across England →

Most recent observation23 October 2025Hartfield · 16 fish
Largest measured bullhead
12.7 cm
Median length
6.5 cm
Fish measured
877
Survey locations
13

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
12.7 cm15 Oct 2024Hartfield168392
12.1 cm14 Aug 2012D/s Weirwood Reservoir132885
10.9 cm7 Aug 2002D/s Weirwood Reservoir66100
10.6 cm12 May 2004D/s Weirwood Reservoir80045
10.6 cm12 May 2004D/s Weirwood Reservoir80045
10.5 cm23 Oct 2025Hartfield180382
10.5 cm12 May 2004D/s Weirwood Reservoir80045
10.5 cm19 Jul 2001D/s Weirwood Reservoir22476
10.2 cm26 Aug 2021Hartfield160779
10.2 cm12 May 2004D/s Weirwood Reservoir80045

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
Hartfield23 Aug 200123 Oct 202524
Penshurst22 Nov 200116 Oct 202517
D/s Ashurst Road Bridge10 Aug 200418 Sept 202510
D/s Weirwood Reservoir19 Jul 20019 Sept 202517
Sovereign Way Tonbridge1 Sept 201025 Jul 20238
Fordcombe14 Nov 20016 Sept 201714
Ashdown House Farm11 Aug 201125 Aug 20162
Tonbridge Juvenile Fish Seine Netting Survey21 Jun 201321 Jun 20131
Bewleys Weir23 Sept 20023 Sept 20096
Grom/Medway Confluence u/s9 Oct 20079 Oct 20071
Grom/Medway Confluence d/s9 Oct 20079 Oct 20071
Gallypot12 Apr 20043 Oct 20072
Ham Farm25 Sept 200225 Sept 20021

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

2001–2025

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 877 measured fish were spread across different length ranges.

Smallest
0.7 cm
Lower quarter
5.3 cm
Median
6.5 cm
Upper quarter
7.6 cm
Largest
12.7 cm

Lengths are direct survey measurements rather than anglers’ catches.

Fish weighed by surveyors

Measured weight summary

Recorded weights were available for 25 bullhead. This is a subset of the measured fish and may not represent the whole population.

Lightest
0.1 oz (0.003 kg)
Lower quarter
0.3 oz (0.008 kg)
Median
0.4 oz (0.01 kg)
Upper quarter
0.4 oz (0.012 kg)
Heaviest
2.5 oz (0.072 kg)

These are direct individual weights recorded by Environment Agency surveyors. Combined bulk weights are not included.

More fish in this river

Explore the River Medway

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

Chub Gudgeon Roach Perch Bleak Dace

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 →