Spate · Granite · Brittany / Côtes-d'Armor, FR

Trieux

A wide panoramic view of the wooded Trieux river valley with the tidal river visible below.

Small Brittany stream with wild trout on Armorican granite.

Poor · Brown Trout
Pheasant Tail Nymph · 14–18
Closed season
Out of season. Try elsewhere.
Closed — confidence not applicable today.
What moved it
  • Level0.19 mLast reading 3h ago
  • Water temp8.9°C
  • ClarityClear
Today's fly
Pheasant Tail Nymph
Pheasant Tail Nymph14–18
Upstream
Conditions on the water
Live gauge
Level
Steady
0.19 m
Last reading 3h ago
Water temp8.9°C
ClarityClear
Weather8°C
WindE 15 km/h
Pressure1013 hPa
Rain · recent0.9 mm
Rain · ahead7.2 mm

The nearest gauge doesn't record temperatures, so we've estimated it — defer to the river keeper's advice.

Water temperature for Brown Trout
Cool — slow
9°C est.ideal 10–16°C
0°14°28°
How to fish it · for Brown Trout
When
Through the open trout season. Spring olives and grannom; sedges through summer evenings; small dark flies into autumn close.
Where
Pool tails and the seams behind boulders through the Côtes-d'Armor stretches. Breton spate freestone — fish 12 to 24 hours after rain. The Trieux is a typical Côtes-d'Armor spate — short, sharp, wadeable.
Method
Upstream dry to risers; dry-dropper through the riffles. Breton spate freestone — fish 12 to 24 hours after rain on the drop. Long leader, fine tippet.
Kit
9 ft #4 — Breton spate freestone. Floating line, 12 ft leader to 4 lb fluoro. Studded boots.
Likely species
Stoneflies
Gammarids
Hatch timeline · todayPeak at 11am

Hatch predictions

Today's headline hatch shown — see all 6 active hatches hour by hour as a supporter.

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Sub-surface · on the nymphunder the surface

Hatch predictions

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

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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 · November highlighted
J
F
M
A
M
J
J
A
S
O
N
D
Trout seasonSeason
1
2
2
2
2
2
1
March BrownHatch
2
3
2
Late March BrownHatch
2
3
2
Large Brook DunHatch
2
3
2
Large StoneflyHatch
2
3
2

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

Ranked for today
Brown Trout fly box

More balanced than the mountain-river pack. French nymphing still matters, but there is more room for dries, spiders and general searching flies.

Permits & access
Permit required — see local rules.
  • AAPPMA permits.
What's coming
Plan ahead
5-day outlook
Other water nearby · 2
Léguer
25 km
Brown trout · Salmon · Sea trout
Étang Neuf (Saint-Connan)
31 km
Rainbow trout · Brown trout
Gallery · 2
  1. A wide panoramic view of the wooded Trieux river valley with the tidal river visible below.
    View over Trieux River from La Roche-Jagu Chateau
  2. Terrain map of the venue
    Terrain map
About this water

Fly-fishing potential for those willing to seek out intimate water. Spring through early autumn. Not crowded — solitude and wild trout are part of the appeal. Check local AAPPMA for access details and any seasonal restrictions.

Hatches & food

On Atlantic trout rivers in Normandy and Brittany, regional studies and on-the-bank experience point to spring mayflies as the main early driver, a strong band of spring and early-summer caddis as channels warm and open, background buzzer life ticking away right through the year, and terrestrials from wooded banks adding important surface food in summer and early autumn, with autumn olives extending sport wherever trout-season rules allow.

  • Granite
Water quality (WFD)
  • Ecology: Moderate
  • Chemical: Unknown

WFD classification · FRGR0030B

The full read · show the working · for Brown Trout · confidence 90%
How the 0 is built — score × weight = contribution
Temperature80 × 28%22.4
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time55 × 13%7.2
Pressure80 × 7%5.6
Insect activity60 × 12%7.2
Conditions total= 77
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowon-river gaugeobserved
Prey activitysurvey-backed invertebrate datasurvey
What would change the calculation
The dawn and dusk windows score higher than the midday lull.
Directions
Apple MapsGoogle Maps
Seasons & zones
  • Trout 2nd Saturday of March → 3rd Sunday of September

Salmon: Banned (2026) — Brittany 2026 order bans Atlantic salmon and sea trout on all Breton rivers.

Sea trout: Banned (2026) — Brittany 2026 order bans Atlantic salmon and sea trout on all Breton rivers.

Related guides
Pyrenees PlaybookFrench riversEuro Nymphingsubsurface methods
Booking & contacts
At a glance

Trieux is a spate river in Brittany / Côtes-d'Armor, France. The catchment geology is recorded as granite, and the water sits at about 36 m above sea level. The river is described as roughly 72 km long. Species listed for this water: brown trout, salmon and sea trout. The salmon season is recorded as running from CLOSED to CLOSED. The trout season is recorded as running from 2nd Saturday of March to 3rd Sunday of September. Best window recorded for anglers: March–September (trout). Core methods listed: Spey casting; nymphing; dry fly. Level and flow data for this water is linked from 1 gauge. Its Water Framework Directive ecological status is recorded as moderate. Access is recorded as day tickets through the local AAPPMA (angling association). Nearby waters in our listings include Léguer at 25 km and Étang Neuf (Saint-Connan) at 31 km.