RiverFish

3-spined stickleback · Gasterosteus aculeatus

3-spined stickleback in the River Mimram

Largest measured 3-spined stickleback: 6 cm

The largest 3-spined stickleback measured in Environment Agency surveys of the River Mimram was 6 cm, recorded at Codicote restoration u/s on 27 February 2007.

Across 73 measured 3-spined stickleback, the median measured length was 4.2 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 Mimram.

See 3-spined stickleback records across England →

Most recent observation25 September 2025Tewin Flyfishers
Largest measured 3-spined stickleback
6 cm
Median length
4.2 cm
Fish measured
73
Survey locations
21

Individual EA measurements

Largest measured 3-spined stickleback

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

LengthSurvey dateSurvey locationSurvey ID
6 cm27 Feb 2007Codicote restoration u/s104610
5.6 cm12 Jul 2017Fulling Mill152486
5.5 cm21 Feb 2018Codicote Station 2156116
5.4 cm21 Feb 2018Codicote Station 2156116
5.4 cm20 Feb 2018Codicote Station 1156115
5.4 cm28 Feb 2007Codicote restoration middle fixed effort104612
5.4 cm28 Feb 2007Codicote restoration middle fixed effort104612
5.3 cm21 Feb 2018Codicote Station 2156116
5.3 cm21 Feb 2018Codicote Station 2156116
5.2 cm23 Feb 2018Sherrardswood School156118

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

Explore the river

Where 3-spined stickleback were found

Each point marks a survey location with at least one 3-spined stickleback 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 3-spined stickleback
Tewin Flyfishers5 Apr 200725 Sept 202516
Singlers Marsh26 Sept 202426 Sept 20241
Codicote restoration middle fully quant28 Feb 200726 Sept 20243
Duck Trap Wood26 Feb 200730 Aug 20242
Upstream Tewin Fly Fishers3 Oct 20233 Oct 20231
Panshanger quarry15 Jun 20067 Sept 202314
Fulling Mill12 Jul 20174 Apr 20235
Codicote Station 120 Feb 20184 Mar 20203
Tewin flyfishers middle8 Oct 201523 Sept 20192
Tewin Archers16 Oct 201823 Sept 20192
Sherrardswood School23 Feb 201813 Feb 20192
Codicote Station 211 Jul 20176 Feb 20193
Chandlers End, Mill Farm16 Oct 20031 May 20142
Codicote restoration u/s27 Feb 20076 Oct 20122
Panshanger quarry broadwater bypass channel22 Oct 201021 Sept 20112
Codicote restoration middle fixed effort28 Feb 200728 Feb 20071
Rose Farm13 Jul 200613 Jul 20061
Rye end cottages12 Jul 200612 Jul 20061
Upstream Panshanger weir16 Jun 200616 Jun 20061
Codicote bottom farm14 Jun 200614 Jun 20061
u/s Tewin Bury farm13 Jun 200613 Jun 20061

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

2003–2025

Survey records by year

Each bar shows how many survey visits recorded 3-spined stickleback that year.

Fish measured by surveyors

Measured length distribution

See how the 73 measured fish were spread across different length ranges.

Smallest
2.2 cm
Lower quarter
3.4 cm
Median
4.2 cm
Upper quarter
4.8 cm
Largest
6 cm

Lengths are direct survey measurements rather than anglers’ catches.

More fish in this river

Explore the River Mimram

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

Bullhead Brown / sea trout Stone loach Minnow 10-spined stickleback Grayling

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 →