919-acre upland reservoir on the Hiraethog moors above Cerrigydrudion. One of Wales's premier stillwater trout fisheries — boat and bank. Stocked with brown and rainbow trout, with wild browns breeding in feeder streams. Competition venue. Excellent buzzer, Diawl Bach and damsel fishing. Visitor centre and boats from sailing club end.
Rules at a glance
- Free fishing
- Fly only
A respectable few hours, if you choose your moments
Good wave on — drift country. A useful wave. Work the productive shore.
45% confidence — limited data
Live now
Conditions on the water
Trends shown where the gauge supports them
Wind
SW 14 km/h
Gentle breeze
Wave
20 cm ripple
Water temp
—
No reading
Air temp
6°C
Cloud
Broken
Pressure
—
Rain · 24h
0.0 mm
No rain
Some readings unavailable — check directly before fishing.
How to fish · for rainbow trout
The brief
When · where · method · kit
How to fish it · for rainbow trout
When
Cold-water upland — buzzers come on later than the southern reservoirs, May through July. Sedges into September; back-end lures before October close. Wait for the air to warm.
Where
Open water boat marks; the dam end and the eastern bays. Brenig's altitude means weather drives the fishing more than season alone.
Method
Floater with buzzers under indicator in late spring; midge-tip with team of three through summer; lures on intermediate when fish are deep.
Kit
10 ft #7 boat rod; floating, intermediate and fast-intermediate lines; 6 to 8 lb fluoro. Drogue and a long-handled net.
Today's tactical plan
The plan
Plan A · Plan B · what to watch · bank or boat
The plan
Plan A
Start with Blob (8-10) on a fast strip on floating line or static on sinking. Rainbows respond to more active retrieves — try short strips between pauses. If that does not produce, switch depth or speed before changing the pattern entirely. When no hatch is visible, a buzzer team — black stripped quill on the point, attractor or pearl-rib on the top dropper — is the default starting point on any UK stillwater.
Plan B
If fish refuse on top, drop to a buzzer under an indicator at different depths.
Watch for
Keep an eye on changing conditions — wind shifts and cloud breaks can trigger short feeding spells.
Either bank or boat
Good ripple suits both bank and boat. Bank: work inflows, dam walls, and points. Boat: broadside drift covering wind lanes.
Hatches & runs
What's on, when
Twelve months at a glance
Through the year
0–3 scale · May highlighted
J
F
M
A
M
J
J
A
S
O
N
D
Trout seasonSeason
1
2
2
2
2
2
2
1
Black MidgeHatch
2
3
3
3
3
3
3
3
3
3
3
2
Reservoir BuzzerHatch
2
3
3
3
3
3
2
Daphnia SwarmHatch
2
3
3
3
2
Lake OliveHatch
2
3
3
3
3
3
2
Numbers are intensity 0 (none) to 3 (peak) — a guide, not a guarantee.
Today's fly · curated pack
Top pattern + the box
5 patterns from this venue's curated pack
Evidence
Why today scores what it does
The factors driving today's verdict
Why this score
- Cloud cover (mixed) suits the fishery well.
Detail · next 12h
Precipitation
The reading most likely to move tomorrow's verdict
About this water · Lough note · 4 min read
Llyn Brenig · profile
Who this water suits
Strengths · watch-outs · best for
About this water
Llyn Brenig, on the water
Field guide · contributor-editedLlyn Brenig · about
What this water is
Background · character · contributors
About this water
919-acre upland reservoir on the Hiraethog moors above Cerrigydrudion. One of Wales's premier stillwater trout fisheries — boat and bank. Stocked with brown and rainbow trout, with wild browns breeding in feeder streams. Competition venue. Excellent buzzer, Diawl Bach and damsel fishing. Visitor centre and boats from sailing club end.
- Reservoir
- Slate
Llyn Brenig · directions
How to get to the water
Directions
Llyn Brenig · zones
Where the rules change
Seasons · zones · per-species rules
Seasons & zones
- Trout26 March → 15 October
Llyn Brenig
Google Places
919-acre upland reservoir on the Hiraethog moors above Cerrigydrudion.
Species
A respectable few hours, if you choose your moments
Good wave on — drift country. A useful wave. Work the productive shore.
45% confidence — limited data
Conditions
Wind
SW 14 km/h
Gentle breeze
Wave
20 cm ripple
Water temp
—
No reading
Air temp
6°C
Cloud
Broken
Pressure
—
Rain · 24h
0.0 mm
No rain
Some readings unavailable — check directly before fishing.
Condition match
64%
Cloud100%
Wind65%
Temp25%
A reasonable day here, though temperature isn't quite in the sweet spot.
How to fish it · for rainbow trout
When
Cold-water upland — buzzers come on later than the southern reservoirs, May through July. Sedges into September; back-end lures before October close. Wait for the air to warm.
Where
Open water boat marks; the dam end and the eastern bays. Brenig's altitude means weather drives the fishing more than season alone.
Method
Floater with buzzers under indicator in late spring; midge-tip with team of three through summer; lures on intermediate when fish are deep.
Kit
10 ft #7 boat rod; floating, intermediate and fast-intermediate lines; 6 to 8 lb fluoro. Drogue and a long-handled net.
The plan
Plan A
Start with Blob (8-10) on a fast strip on floating line or static on sinking. Rainbows respond to more active retrieves — try short strips between pauses. If that does not produce, switch depth or speed before changing the pattern entirely. When no hatch is visible, a buzzer team — black stripped quill on the point, attractor or pearl-rib on the top dropper — is the default starting point on any UK stillwater.
Plan B
If fish refuse on top, drop to a buzzer under an indicator at different depths.
Watch for
Keep an eye on changing conditions — wind shifts and cloud breaks can trigger short feeding spells.
Either bank or boat
Good ripple suits both bank and boat. Bank: work inflows, dam walls, and points. Boat: broadside drift covering wind lanes.
Why this score
- Cloud cover (mixed) suits the fishery well.
Through the year
0–3 scale · May highlighted
J
F
M
A
M
J
J
A
S
O
N
D
Trout seasonSeason
1
2
2
2
2
2
2
1
Black MidgeHatch
2
3
3
3
3
3
3
3
3
3
3
2
Reservoir BuzzerHatch
2
3
3
3
3
3
2
Daphnia SwarmHatch
2
3
3
3
2
Lake OliveHatch
2
3
3
3
3
3
2
Numbers are intensity 0 (none) to 3 (peak) — a guide, not a guarantee.
Gallery · 1
Terrain map
Directions
About this water
919-acre upland reservoir on the Hiraethog moors above Cerrigydrudion. One of Wales's premier stillwater trout fisheries — boat and bank. Stocked with brown and rainbow trout, with wild browns breeding in feeder streams. Competition venue. Excellent buzzer, Diawl Bach and damsel fishing. Visitor centre and boats from sailing club end.
- Reservoir
- Slate
Seasons & zones
- Trout26 March → 15 October
About this water · Lough note · 4 min read
919-acre upland reservoir on the Hiraethog moors above Cerrigydrudion. One of Wales's premier stillwater trout fisheries — boat and bank. Stocked with brown and rainbow trout, with wild browns breeding in feeder streams. Competition venue. Excellent buzzer, Diawl Bach and damsel fishing. Visitor centre and boats from sailing club end.
Other water nearby · 5
Booking & contacts