Lowland · Mixed · East / Louth-Monaghan

Monaghan Blackwater

Monaghan Blackwater — A river runs through it

The Monaghan Blackwater rises near the Bragan mountains and runs through Monaghan town toward the Ulster Blackwater at Caledon.

Marginal · Brown Trout
Pheasant Tail Nymph · 14-18
Marginallive now
Slow going — pick your moments
River temperature is the limiting factor today, not the flow. Fish dawn or dusk if you go at all, and handle everything with extra care.
80% confidence
What moved it
  • LevelProxyvia River Fane
  • Water temp19.0°C
  • ClarityClear
Today's fly
Pheasant Tail Nymph
Pheasant Tail Nymph14-18
Upstream
Conditions on the water
Proxy gauge
Level
Steady
Proxy
via River Fane
Water temp19.0°C
ClarityClear
Weather25°C
WindSW 17 km/h
Pressure1018 hPa
Rain · recent0.0 mm
Rain · ahead1.3 mm

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

Water temperature for Brown Trout
Warm — slow
19°C est.ideal 1016°C
0°14°28°
How to fish it · for Brown Trout
When
Nymphing can work through most of the day.
Where
Cover mixed depths.
Method
Start with tight-line nymphs and adjust if fish rise or drift higher.
Kit
9 ft #4 rod, floating line, 12 ft tapered leader to 4–5 lb fluoro tippet.
Why this works
Water at 19°C — above the brown trout caution line (18°C). Fish dawn or dusk only. Land it fast, wet hands, no air shots.
Hatch timeline · todayPeak at 6pm

Hatch predictions

Today's headline hatch shown — see all 10 active hatches hour by hour with Pro.

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Sub-surface · on the nymphunder the surface

Hatch predictions

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Beyond the hatch · worth watchingambient prey

Hatch predictions

Top prey shown — see all 3 with Pro.

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Evidence
Survey-backed · regionalHigh confidence

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

Updated 6 hours ago

Through the year
0–3 scale · August highlighted
J
F
M
A
M
J
J
A
S
O
N
D
Trout seasonSeason
1
2
2
2
2
2
1
Daddy Long LegsHatch
2
3
2
Terrestrial BeetlesHatch
2
3
3
2
Blue Winged OliveHatch
1
2
2
2
2
1
Black MidgeHatch
1
2
2
2
2
2
2
2
2
2
2
1

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

Ranked for today
Brown Trout fly box
What's coming
Plan ahead
5-day outlook
Water here around 19°C. Nothing cooler within range — carry a thermometer.
Gallery · 2
  1. Monaghan Blackwater — A river runs through it
    A river runs through it
  2. Terrain map of the venue
    Terrain map
About this water

The Monaghan Blackwater rises near the Bragan mountains and runs through Monaghan town toward the Ulster Blackwater at Caledon. It carries wild and stocked brown trout, and increasingly the Dollaghan — the fast-growing migratory trout of Lough Neagh, which runs the river and is best fished after dark, much as you would fish for sea trout. A small salmon run arrives late in the season. Monaghan Anglers Association stocks and manages the water; day tickets are about €5.

Hatches & food

A limestone-influenced drumlin river with decent olive and sedge hatches; midges and sedges matter most after dark for the Dollaghan and sea trout, which behave like night-feeding sea trout rather than dry-fly risers.

  • Mixed
The full read · show the working · for Brown Trout · confidence 80%
How the 34 is built — score × weight = contribution
Temperature39 × 28%10.9
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time80 × 13%10.4
Pressure80 × 7%5.6
Insect activity65 × 12%7.8
Conditions total= 69
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowproxy via River Faneproxy
Prey activitysurvey-backed invertebrate datasurvey
What would change the calculation
Cooler water — back toward the 10–16 °C ideal band — would lift the score and ease welfare.
Directions
Seasons & zones
  • Trout 1 March30 September

Sea trout: Variable seasonal (2026)

Related guides
Casting instructors near here
Booking & contacts
Permits & access