Lowland · Mixed · East / Louth-Monaghan, IE

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.

Fair · Sea Trout
Black & Silver Tube · 1-2 inch
Fairlive now
Decent — worth a look
River lifting fast on the rain. Wait for the rise to peak before settling on a beat.
65% confidence
What moved it
  • Level0.93 mDropping after lift
  • Water temp13.3°C
  • ClarityClearingClearing
Today's fly
BS
Black & Silver Tube1-2 inch
In deep pools and dark water, silhouette and contrast do the work colour cannot. A fly that reads as black against depth is enough. Fish it broadside, hold the swing, let it hang at the dangle — that is when the best fish take.
Conditions on the water · Tomorrow
Live gauge
Level
Falling
0.93 m
Dropping after lift
Water temp13.3°C
ClarityClearing
Weather11°C
WindN 18 km/h
Pressure1019 hPa
Rain · recent2.1 mm
Rain · ahead3.4 mm

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

Water temperature for Sea Trout
Ideal
13°C est.ideal 8–15°C
0°14°28°
How to fish it · for Sea Trout
When
From dusk into the first half of the night.
Where
Deeper pools and slower glides · hold water and current seams.
Method
Fish dark patterns on a sink-tip or lightly sunk line, especially near structure.
Kit
10 ft #6/7 rod, floating line with a sink-tip option, 8–10 lb fluoro tippet for the swing.
Why this works
Good — water temperature is working for you, but time of day is the limiting factor today.
Likely species
Mayflies
Caddisflies
Gammarids
Hatch timeline · todayPeak at 6pm

Hatch predictions

Today's headline hatch shown — see all 12 active hatches hour by hour as a supporter.

Start free trial

14-day free trial. Cancel anytime.

Sub-surface · on the nymphunder the surface

Hatch predictions

Top nymph shown — see all 2 guilds as a supporter.

Start free trial

14-day free trial. Cancel anytime.

Beyond the hatch · worth watchingambient prey(1)

Hatch predictions

Top prey shown — see all 4 as a supporter.

Start free trial

14-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
Mayfly (Green Drake)Hatch
2
2
Large Cinnamon SedgeHatch
2
3
3
2
Daddy Long LegsHatch
2
3
2
CapererHatch
2
3
3
2

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

Ranked for today
Sea Trout fly box
BS
Black & Silver TubeTop
1-2 inch · Tube
In deep pools and dark water, silhouette and contrast do the work colour cannot. A fly that reads as black against depth is enough. Fish it broadside, hold the swing, let it hang at the dangle — that is when the best fish take.
Medicine Fly
Medicine Fly
8-12 · Streamer
Slim and mobile — fished sunk through the pool when surface work is not producing. Consistently takes fish that will not come to the surface.
SF
Snake Fly (Black)
2-4 inch · Streamer
A mobile eel-like profile that undulates through deep pools — effective when sea trout are lying deep and not responding to conventional wets.
What's coming
Plan ahead
5-day outlook
Other water nearby · 5
Emy Lough
10 km
Brown trout · Pike
Lough Corry
20 km
Brown trout
Corranny Lake
22 km
Rainbow trout
Annagh Lake
35 km
Brown trout · Rainbow trout
Annaginny Fishery
35 km
Rainbow trout
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
Why this score · for Sea Trout
  • Temperature10028% weight
  • Flow5522% weight
  • Clarity4518% weight
  • Feeding Time2513% weight
  • Pressure857% weight
  • Insect activity5412% weight
Directions
Apple MapsGoogle Maps
Seasons & zones
  • Trout 1 March → 30 September

Sea trout: Variable seasonal (2026)

Related guides
ConnemaraIrish fishingEuro Nymphingsubsurface methods
Casting instructors near here
Booking & contacts
Permits & access