Direct individual measurements
Largest topmouth gudgeon by waterway
Ranked by the largest individual measured in EA surveys. The sample size shows how many valid length measurements underpin each waterway's figures.
| Rank | River or waterway | Largest | Median | Measured | Measured at |
|---|---|---|---|---|---|
| 1 | Turkey BrookSouth East | 9 cm (3.5 in) | 5.2 cm (2 in) | 48 | 27 Nov 2013Rotenone neutralisation zone |
| 2 | Cuffley BrookSouth East | 7.9 cm (3.1 in) | 5.9 cm (2.3 in) | 19 | 27 Nov 2013Rotenone treatment zone |
| 3 | River TestSouth East | 7.6 cm (3 in) | 5 cm (2 in) | 26 | 14 Sept 2020Romsey Canal |
| 4 | River Main Bristol FromeSouth West | 7 cm (2.8 in) | 7 cm (2.8 in) | 1 | 26 Jul 2022Damsons Bridge (Te) |
| 5 | Tadburn LakeSouth East | 6.1 cm (2.4 in) | 5.4 cm (2.1 in) | 3 | 19 Sept 2023Crampmoor Ford |
| 6 | Lee NavigationSouth East | 5 cm (2 in) | 5 cm (2 in) | 1 | 2 Sept 2004Ponders End |
Equal maximum lengths are ordered by sample size. Measurements are shown as recorded and are not converted into estimated weights.
98 fish measured
Measured topmouth gudgeon lengths
The median divides the measured sample in half. This distribution describes surveyed fish, not every topmouth gudgeon living in England.
Only positive individual lengths that pass RiverFish's general measurement checks are included. Each bar covers a 20 mm range.
Latest EA evidence
Latest topmouth gudgeon observations
The ten most recent survey visits that recorded topmouth gudgeon in named waterways.
| Date | River or waterway | Survey location | Fish recorded |
|---|---|---|---|
| 30 Jun 2026 | Turkey Brook | Forty Hall | 1 |
| 19 Sept 2023 | Tadburn Lake | Crampmoor Ford | 3 |
| 15 Sept 2023 | Tadburn Lake | Ashdown Way | 9 |
| 14 Sept 2023 | River Test | Romsey Canal | 12 |
| 26 Jul 2022 | River Main Bristol Frome | Damsons Bridge (Te) | 1 |
| 21 Sept 2021 | River Test | Romsey Canal | 12 |
| 14 Sept 2020 | River Test | Romsey Canal | 2 |
| 26 Mar 2014 | Cuffley Brook | Flash Lane | 1 |
| 25 Mar 2014 | Cuffley Brook | Glasgow Stud 2 | 1 |
| 13 Dec 2013 | Cuffley Brook | Glasgow Stud 2 | 1 |
A survey record confirms topmouth gudgeon at that place and time. It does not show present-day abundance or fishing access.
20 positive survey visits
Survey distribution
EA surveys recorded topmouth gudgeon at 14 locations across 6 named waterways represented on RiverFish.
| Region | Waterways | Locations | Survey visits | Latest record |
|---|---|---|---|---|
| South East | 5 | 13 | 19 | 30 Jun 2026 |
| South West | 1 | 1 | 1 | 26 Jul 2022 |
3 detailed pages
Topmouth gudgeon by river
Open any river-specific page for its measured lengths, largest surveyed individuals, locations and observation history.
How to read this page
Survey measurements, not angling records
Environment Agency surveys are designed to monitor fish populations. Their largest measurement is not equivalent to a verified rod-and-line record, and the survey sample does not include every river or every topmouth gudgeon.
Waterway groups with administrative or mixed-river labels are excluded from the headline national totals and rankings. Their eligible river-specific pages remain available in the directory so no published destination is hidden.
The fish records use the Environment Agency source snapshot dated 10 August 2026.
How RiverFish handles the data →