RiverFish

Bullhead · Cottus gobio

Bullhead in the Roman River (Headwaters)

Largest measured bullhead: 10.2 cm

The largest bullhead measured in Environment Agency surveys of the Roman River (Headwaters) was 10.2 cm, recorded at Colchester Zoo on 16 September 2024.

Across 143 measured bullhead, the median measured length was 6 cm.

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

See bullhead records across England →

Most recent observation5 October 2025Colchester Zoo · 18 fish
Largest measured bullhead
10.2 cm
Median length
6 cm
Fish measured
143
Survey locations
1

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
10.2 cm16 Sept 2024Colchester Zoo168810
10 cm25 Oct 2023Colchester Zoo164462
10 cm9 Sept 2021Colchester Zoo160294
9.8 cm9 Sept 2021Colchester Zoo160294
9.7 cm9 Sept 2021Colchester Zoo160294
9.6 cm25 Oct 2023Colchester Zoo164462
9.6 cm25 Oct 2023Colchester Zoo164462
9.6 cm4 Oct 2022Colchester Zoo162099
9.5 cm25 Oct 2023Colchester Zoo164462
9.4 cm16 Sept 2024Colchester Zoo168810

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
Colchester Zoo12 Oct 20185 Oct 20257

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

2018–2025

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 143 measured fish were spread across different length ranges.

Smallest
3.9 cm
Lower quarter
5.3 cm
Median
6 cm
Upper quarter
7.5 cm
Largest
10.2 cm

Lengths are direct survey measurements rather than anglers’ catches.

More fish in this river

Explore the Roman River (Headwaters)

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

Stone loach European eel 3-spined stickleback Brown / sea trout Roach 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 →