Freestone · Limestone · Gorenjska / Bohinj (Stara Fužina)

Mostnica

Mostnica — Mostnica Gorge

The Mostnica cuts a slot gorge above Stara Fužina before it settles into the Bohinjka — most people know it for the gorge walk, which means the fishing gets left alone by the tourists photographing the potholes.

Prime · Brown Trout
Elk Hair Caddis · 12-16
Primelive now
About as good as it gets
River high but settled. Coloured water — fish bigger and deeper, confident takes down the seams.
90% confidence
What moved it
  • Level103.00 m
  • Water temp12.8°C
  • ClarityClear
Today's fly
Elk Hair Caddis
Elk Hair Caddis12-16
High-confidence seasonal pick
Conditions on the water
Live gauge
Level
Steady
103.00 m
Water temp12.8°C
ClarityClear
Weather20°C
WindN 6 km/h
Pressure1021 hPa
Rain · recent0.0 mm
Rain · ahead0.4 mm

Live readings only. Trends shown where the gauge supports them.

Water temperature for Brown Trout
Ideal
12.8°Cideal 10–16°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
Excellent — water temperature is right today, though time of day could be better.
Likely species
Mayflies
  • Large dark oliveMost likely
    #14–16 · Emerger
    Dead-drift the emerger — it's sitting in the film.
  • Blue-winged oliveAlso possible
    #16–18 · Dun
    Duns are up; a sherry spinner fall may follow.
  • Anglers curse mayfliesAlso possibleLower confidence
    #20–22 · Spinner
    Go tiny: 20-22 spent spinner, single fly, long tippet.
Caddisflies
  • Net-spinning caddis (S. Europe)Most likelyLower confidence
    #12–14–16 · Pupa
    Widespread riffle net-spinner; evening emergence.
  • Satin sedgeAlso possibleLower confidence
    #12–14 · Egg-laying
    Skitter it at dusk — this one's fished, not dead-drifted.
Hatch timeline · todayPeak at 6pm

Hatch predictions

Today's headline hatch shown — see all 8 active hatches hour by hour with Pro.

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Sub-surface · on the nymphunder the surface

Hatch predictions

Top nymph shown — see all 4 guilds with Pro.

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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
ModelledModerate confidence

Modelled from regional ecology — no survey or occurrence data for this water yet.

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
GrannomHatch
2
2
Evening SedgeHatch
2
3
3
3
2
Alpine RhithrogenaHatch
1
2
2
1
Large Dark OliveHatch
1
2
2
1

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

Ranked for today
Brown Trout fly box

Ultra-clear spring-fed rivers with large educated trout. Sight fishing, technical presentation, fine tippets. Euro-nymphing dominant subsurface method. Exceptional dry-fly windows during hatch periods. Gacka is the flagship water.

Permits & access
Permit required — see local rules.
  • RD Bohinj
  • Fly-only, barbless
  • Gorge reach is a tourist walk, not practically fishable.
What's coming
Plan ahead
5-day outlook
Other water nearby · 5
Sava Bohinjka
2.0 km
72
Brown trout · Marble trout · Rainbow trout
Savica
4.0 km
Brown trout · Lake trout
Soča
12 km
Brown trout · Marble trout
Koritnica (Bača tributary, Rut)
13 km
Marble trout · Brown trout · Grayling
Tolminka
15 km
Marble trout · Marble brown hybrid trout · Brown trout
Gallery · 2
  1. Mostnica — Mostnica Gorge
    Mostnica Gorge
  2. Terrain map of the venue
    Terrain map
About this water

The Mostnica cuts a slot gorge above Stara Fužina before it settles into the Bohinjka — most people know it for the gorge walk, which means the fishing gets left alone by the tourists photographing the potholes. Small water, marble and brown trout, best fished below the gorge where you can actually get a fly on it without abseiling.

  • River
  • Limestone
The full read · show the working · for Brown Trout · confidence 90%
How the 84 is built — score × weight = contribution
Temperature100 × 28%28.0
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time60 × 13%7.8
Pressure80 × 7%5.6
Insect activity62 × 12%7.4
Conditions total= 84
Can you trust it?
Water temperaturelive gauge readinggauge
Level / flowon-river gaugeobserved
Prey activitymodelled from regional profilemodelled
What would change the calculation
The dawn and dusk windows score higher than the midday lull.
Directions
Apple MapsGoogle Maps
Seasons & zones
  • Trout 1 March → 30 September
  • Marble trout 1 April → 31 October
Related guides
Alpine Streamsmountain entomologyMarble TroutSoča systemEuro Nymphingsubsurface methods
Booking & contacts