River Monnow
7 fish species have been recorded at 9 locations along the River Monnow.
- Fish species
- 7
- Places surveyed
- 9
- Survey visits
- 57
- Records span
- 1987–2025
Local EA evidence
Where fish were recorded
Choose a point on the map to see what was recorded there.
Check local permissions before fishing.
River conditions
Environment Agency evidence
Fish found in this river
Open a linked fish for detailed measurements, or use the map filter above to compare survey locations.
| Fish | Sites | Most recent | Fish counted | Measured length | Measured weight |
|---|---|---|---|---|---|
| Brown / sea troutSalmo trutta | 9 | 2025 | 1,445 | Median: 9.2 cm1,115 fish measuredLargest measured brown / sea trout: 38 cm | — |
| BullheadCottus gobio | 9 | 2025 | 431 | Median: 6.8 cm155 fish measuredLargest measured bullhead: 11.3 cm | — |
| European eelAnguilla anguilla | 9 | 2025 | 47 | Median: 37 cm39 fish measuredLargest measured european eel: 60 cm | Median: 2 oz (0.058 kg)8 fish weighedLargest measured: 4.6 oz (0.13 kg) |
| Stone loachBarbatula barbatula | 9 | 2025 | 18 | Median: 4.6 cm14 fish measuredLargest measured stone loach: 10.6 cm | — |
| MinnowPhoxinus phoxinus | 7 | 2025 | 594 | Median: 4.3 cm20 fish measuredLargest measured minnow: 7.4 cm | — |
| GraylingThymallus thymallus | 3 | 2003 | 1 | Recorded length: 9.1 cm1 fish measuredView grayling measurement → | — |
| 3-spined sticklebackGasterosteus aculeatus | 1 | 2019 | — | — | — |
EA surveys have recorded these fish at particular sites and times. Absence from a survey is not evidence that a species is absent from the river. Every valid individual length and weight is retained, with its sample size shown.
Useful context
This page follows survey locations along the main River Monnow. Tributaries and unrelated rivers with similar names are kept separate.
The map shows past fish records, not fishing access or a promise of what you’ll catch today.
How RiverFish handles the data →