Spate · Old Red Sandstone · Mid Wales / Powys (Black Mountains, Wye tributary via Talgarth)

Llynfi

The Afon Llynfi river near Pontithel in Powys, Wales, flanked by trees and fields.

A Black Mountains spate stream — the Llynfi and its own tributary the Llynfi Dulas — running off Old Red Sandstone ground down through Talgarth to join the Wye near Glasbury.

Tomorrow · About as good as it gets
Elk Hair Caddis
Forecast · Tomorrow
About as good as it gets
On the feed top to bottom — start on the rises with a dry, drop a nymph if they stay down.
90% projected
Today's fly
Elk Hair Caddis
Elk Hair Caddis
Conditions on the water · Tomorrow
Proxy gauge
Level
Steady
Proxy
via Wye
Water temp12.4°C
ClarityClear
Weather11°C
WindN 23 km/h
Pressure1015 hPa
Rain · recent0.0 mm
Rain · ahead0.0 mm

No gauge on this water — conditions are inferred from Wye. The trend transfers, the absolute level does not.

Water temperature for European Perch
Ideal
12°C est.ideal 12–20°C
0°14°28°
How to fish it · for European Perch
Where
A Black Mountains spate stream — the Llynfi and its own tributary the Llynfi Dulas — running off Old Red Sandstone ground down through Talgarth to join the…
Why this works
Very poor — water temperature is working for you, but river flow is the limiting factor today.
Likely species
Stoneflies
Gammarids
Hatch timeline · tomorrowPeak at 6pm

12pm(now) — Autumn Needle Fly

Stage: Creeping nymphsApproach: Heavy nymphActivity: 60%
Also:Daddy Long Legs43%Iron Blue41%
Peak emergence window8 food groups active

Peak activity at 6pm — Caperer (Caperer, 10 food groups active)

Sub-surface · on the nymphunder the surface

Hatch predictions

Top nymph shown — see all 3 guilds as a supporter.

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Beyond the hatch · worth watchingambient prey(1)

Hatch predictions

Supporters see what else is on the menu.

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Evidence
Survey-backed · regionalHigh confidence

Backed by regional invertebrate surveys; no sampling on this exact reach yet.

Through the year
0–3 scale · October highlighted
J
F
M
A
M
J
J
A
S
O
N
D
March BrownHatch
2
3
2
CapererHatch
2
3
3
2
Heather FlyHatch
2
2
Autumn DunHatch
2
3
2

Numbers are intensity 0 (none) to 3 (peak) — a guide, not a guarantee.

Ranked for today
European Perch fly box

Traditional wild-trout llyn fishing. Wet flies and dabblers stay central, with buzzer, caddis, terrestrials and occasional small fry patterns becoming important as the season warms.

Beats · 4 · 1 reaches
Llynfi beats — Fishing Passport · 4 beatsDay rods
Llynfi Dulas — Lower, Llynfi Dulas — Middle, Talgarth, Pontithel
The 4 beats
Llynfi Dulas — LowerDay tickets
Wye & Usk Foundation (Fishing Passport — Wild Streams)
1.25 miles from the Llynfi confluence up to Tregunter Farm — short, overgrown single (right) bank near the start, opening to double bank past a caravan park. One of the highest trout densities of any Wye tributary. Spectacular mayfly hatch. 2 fish/rod limit, sub-9in returned.
Wild Stream pre-booking or Season Permit.
Visit official site ↗
Llynfi Dulas — MiddleDay tickets
Wye & Usk Foundation (Fishing Passport — Wild Streams)
Over 1 mile of single-bank Llynfi Dulas from Tregunter Farm up to Pont-y-Bat bridge — part of over 4 miles of Wild Streams access on the Llynfi and Llynfi Dulas combined, plus a further mile of Llynfi via the Booking Office.
Wild Stream pre-booking or Season Permit. Chest waders really required.
Visit official site ↗
TalgarthDay tickets
Wye & Usk Foundation (Fishing Passport — Wild Streams)
~1 mile mixed double/single-bank River Llynfi near Talgarth, extended in 2019 below Bronllys Castle bridge. The widest species list of any Wild Streams beat — wild brown trout plus grayling, chub and shoals of perch.
Wild Stream pre-booking or Season Permit. Full C&R, mandatory online catch return.
Visit official site ↗
PontithelDay tickets
Wye & Usk Foundation (Fishing Passport — Wild Streams)
~0.75 mile double-bank River Llynfi, 2 miles upstream of the Llynfi/Wye confluence, near Pontithel. Trout and grayling, with some large fish present; a dedicated Winter Grayling ticket is also sold.
Wild Stream pre-booking or Season Permit. Felt/studded soles necessary despite straightforward wading.
Visit official site ↗
What's coming
Plan ahead
5-day outlook
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Gallery · 2
  1. The Afon Llynfi river near Pontithel in Powys, Wales, flanked by trees and fields.
    The Afon Llynfi near Pontithel, Powys, flowing through the Wye valley countryside.
  2. Terrain map of the venue
    Terrain map
About this water

A Black Mountains spate stream — the Llynfi and its own tributary the Llynfi Dulas — running off Old Red Sandstone ground down through Talgarth to join the Wye near Glasbury. Fishing Passport's Wild Streams scheme covers over 4 miles here, and it's reckoned among the best wild brown trout density of any Wye tributary, with a genuine mayfly hatch, some grayling, and the widest species list of any Wild Streams beat lower down (chub and perch alongside the trout).

  • Old red sandstone
The full read · show the working · for European Perch · confidence 62%
Perfect · stillwater comfort — temperature and low-light led
Water temperatureWater temp 13°C — prime band for european perch.
FlowFlow not a major driver — focus on temperature and clarity.
LightOvercast helps — low light is the species preference.
SeasonPrime month for this species.
Water clarityClarity very coloured — accounted for via spook-risk.
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowproxy via Wyeproxy
Related guides
Grayling Playbookgrayling tacticsYorkshire & SpidersNorth Country methodsEuro Nymphingsubsurface methods
Casting instructors near here
Booking & contacts
Boards & regulators