Mayflies
Caddisflies
Gammarids
- Ecology: Good
- Chemical: Unknown
WFD classification · BERW06_OU06R
Rules at a glance
- Day tickets
Water temperature for Grayling
Ideal14°C est.ideal 4–14°C
0°14°28°
How to fish it · for Grayling
When
Midday window — grayling feed best from late morning into early afternoon.
Where
Work runs and glides — grayling shoal in the bottom third of the water column.
Method
Tight-line nymph the bottom third with weighted patterns.
Kit
10 ft #3 rod, floating line, long leader to 4 lb fluoro for nymphs.
Why this works
Good — water temperature is working for you, but time of day is the limiting factor today.
Likely species
Caddisflies
- Large sedgesMost likelyNearest relative#8–10 · AdultBig waked sedge in the last light and after dark.
- Net-spinning caddisAlso possibleLower confidenceNearest relative#12–14–16 · PupaWidespread riffle net-spinner; evening emergence.
- CapererAlso possibleLower confidence#10–12 · AdultBig autumn sedge; fish dry at last light.
- Green SedgeAlso possibleLower confidenceNearest relative#10–12–14–16 · NymphFree-living green caddis larva; fast stony riffles.
Hatch timeline · todayPeak at 14h
12h(now) — Reed Smut
Stage: On emergersApproach: Emerger or dryActivity: 44%
Also:Heather Fly39%Pale Watery26%Cinnamon Sedge26%
Peak emergence window10 food groups active
Peak activity at 14h — Autumn Dun (Autumn Dun, 12 food groups active)
Sub-surface · on the nymphunder the surface
Hatch predictions
Top nymph shown — see all 2 guilds as a supporter.
Start free trial14-day free trial. Cancel anytime.
Beyond the hatch · worth watchingambient prey(1)
Hatch predictions
Top prey shown — see all 5 as a supporter.
Start free trial14-day free trial. Cancel anytime.
Evidence
Survey-backed · regionalHigh confidence
Backed by regional invertebrate surveys; no sampling on this exact reach yet.
Through the year
0–3 scale · September highlighted
J
F
M
A
M
J
J
A
S
O
N
D
Trout seasonSeason
1
2
2
2
2
2
1
Grayling seasonSeason
2
1
1
2
2
2
2
2
2
Evening SedgeHatch
2
3
3
3
2
Large Dark OliveHatch
1
2
2
1
Iron BlueHatch
1
2
2
2
2
2
2
1
Blue Winged OliveHatch
1
2
2
2
2
1
Numbers are intensity 0 (none) to 3 (peak) — a guide, not a guarantee.
Ranked for today
Fly box · Grayling
Hook 14–18 · Fly
in season · matches water height
Permits & access
Permit required — see local rules.
- Permis de pêche (Wallonia) / Visverlof (Flanders)
- Foreign anglers can purchase a Walloon fishing permit (permis de pêche) online or at post offices without residency requirements
- For Flemish waters, the visverlof is similarly available
- No prior fishing exam required in either region.
What's coming
Plan ahead
5-day outlook
Other water nearby · 5
Gallery · 2
Ourthe Terrain map
Water quality (WFD)
The full read · show the working · for Grayling · confidence 55%
How the 76 is built — score × weight = contribution
Temperature100 × 28%28.0
Flow80 × 22%17.6
Clarity85 × 18%15.3
Feeding Time10 × 13%1.3
Pressure80 × 7%5.6
Insect activity66 × 12%7.9
Conditions total= 76
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
Seasons & zones
- Trout 3e Saturday de March → 30 September
- Grayling 1 June → 28 February
Related guides
Booking & contacts
Ourthe
Water temperature for Grayling
Ideal14°C est.ideal 4–14°C
0°14°28°
How to fish it · for Grayling
When
Midday window — grayling feed best from late morning into early afternoon.
Where
Work runs and glides — grayling shoal in the bottom third of the water column.
Method
Tight-line nymph the bottom third with weighted patterns.
Kit
10 ft #3 rod, floating line, long leader to 4 lb fluoro for nymphs.
Why this works
Good — water temperature is working for you, but time of day is the limiting factor today.
Likely species
Caddisflies
- Large sedgesMost likelyNearest relative#8–10 · AdultBig waked sedge in the last light and after dark.
- Net-spinning caddisAlso possibleLower confidenceNearest relative#12–14–16 · PupaWidespread riffle net-spinner; evening emergence.
- CapererAlso possibleLower confidence#10–12 · AdultBig autumn sedge; fish dry at last light.
- Green SedgeAlso possibleLower confidenceNearest relative#10–12–14–16 · NymphFree-living green caddis larva; fast stony riffles.
Hatch timeline · todayPeak at 14h
12h(now) — Reed Smut
Stage: On emergersApproach: Emerger or dryActivity: 44%
Also:Heather Fly39%Pale Watery26%Cinnamon Sedge26%
Peak emergence window10 food groups active
Peak activity at 14h — Autumn Dun (Autumn Dun, 12 food groups active)
Sub-surface · on the nymphunder the surface
Hatch predictions
Top nymph shown — see all 2 guilds as a supporter.
Start free trial14-day free trial. Cancel anytime.
Beyond the hatch · worth watchingambient prey(1)
Hatch predictions
Top prey shown — see all 5 as a supporter.
Start free trial14-day free trial. Cancel anytime.
Evidence
Survey-backed · regionalHigh confidence
Backed by regional invertebrate surveys; no sampling on this exact reach yet.
Through the year
0–3 scale · September highlighted
J
F
M
A
M
J
J
A
S
O
N
D
Trout seasonSeason
1
2
2
2
2
2
1
Grayling seasonSeason
2
1
1
2
2
2
2
2
2
Evening SedgeHatch
2
3
3
3
2
Large Dark OliveHatch
1
2
2
1
Iron BlueHatch
1
2
2
2
2
2
2
1
Blue Winged OliveHatch
1
2
2
2
2
1
Numbers are intensity 0 (none) to 3 (peak) — a guide, not a guarantee.
Ranked for today
Fly box · Grayling
Hook 14–18 · Fly
in season · matches water height
Permits & access
Permit required — see local rules.
- Permis de pêche (Wallonia) / Visverlof (Flanders)
- Foreign anglers can purchase a Walloon fishing permit (permis de pêche) online or at post offices without residency requirements
- For Flemish waters, the visverlof is similarly available
- No prior fishing exam required in either region.
What's coming
Plan ahead
5-day outlook
Other water nearby · 5
Gallery · 2
Ourthe Terrain map
Water quality (WFD)
- Ecology: Good
- Chemical: Unknown
WFD classification · BERW06_OU06R
The full read · show the working · for Grayling · confidence 55%
How the 76 is built — score × weight = contribution
Temperature100 × 28%28.0
Flow80 × 22%17.6
Clarity85 × 18%15.3
Feeding Time10 × 13%1.3
Pressure80 × 7%5.6
Insect activity66 × 12%7.9
Conditions total= 76
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
Seasons & zones
- Trout 3e Saturday de March → 30 September
- Grayling 1 June → 28 February
Related guides
Booking & contacts