Mayflies
Stoneflies
Caddisflies
Gammarids
Small water, marble and brown trout, best fished below the gorge where you can actually get a fly on it without abseiling.
- River
- Limestone
Rules at a glance
- Permit required
- Fly only
- Barbless
Water temperature for Marble Trout
Ideal8.6°Cideal 8–13°C
0°14°28°
How to fish it · for Marble 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
Good — water temperature is right today, though time of day could be better.
Likely species
Mayflies
- Turkey BrownMost likelyLower confidence#14–16 · DunSmall spring dun on slower glides and margins.
- Late March BrownAlso possibleLower confidence#12–14 · DunLate-season upland riffle dun, dusk emergence.
- Iron BlueAlso possibleNearest relative#16–18 · DunCold, grey day — the dun sits long. Good dry-fly water.
Caddisflies
- Green SedgeMost likelyLower confidenceNearest relative#10–12–14–16 · NymphFree-living green caddis larva; fast stony riffles.
- GrannomAlso possibleNearest relative#14–16 · PupaPupa first, then dries as the adults come off.
- Saddle-case CaddisAlso possibleLower confidenceNearest relative#16–18 · AdultTiny blackish caddis; fast riffles, early summer.
Molluscs
- Pond snailsMost likelyLower confidence#10–12–14 · AdultDead-drift or twitch a snail pattern near weed beds.
Oligochaetes
- Aquatic wormsMost likelyLower confidence#12–14–16 · AdultDead-drift a worm pattern deep - a year-round staple.
Hatch timeline · todayQuiet day
Hatch predictions
Today's headline hatch shown — see all 7 active hatches hour by hour as a supporter.
Start free trial14-day free trial. Cancel anytime.
Sub-surface · on the nymphunder the surface
Hatch predictions
Supporters see the full sub-surface read.
Start free trial14-day free trial. Cancel anytime.
Beyond the hatch · worth watchingambient prey(1)
Hatch predictions
Supporters see what else is on the menu.
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Evidence
Records-basedModerate confidence
Based on species-occurrence records, not local invertebrate surveys.
Through the year
0–3 scale · October highlighted
J
F
M
A
M
J
J
A
S
O
N
D
Trout seasonSeason
1
2
2
2
2
2
1
Evening SedgeHatch
2
3
3
3
2
Alpine RhithrogenaHatch
1
2
2
1
Large Dark OliveHatch
1
2
2
1
Iron BlueHatch
1
2
2
2
2
2
2
1
Numbers are intensity 0 (none) to 3 (peak) — a guide, not a guarantee.
Ranked for today
Marble 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
Gallery · 2
Mostnica Gorge Terrain map
About this water
The full read · show the working · for Marble Trout · confidence 75%
How the 76 is built — score × weight = contribution
Temperature100 × 28%28.0
Flow60 × 22%13.2
Clarity95 × 18%17.1
Feeding Time45 × 13%5.9
Pressure80 × 7%5.6
Insect activity48 × 12%5.8
Conditions total= 76
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
Seasons & zones
- Trout 1 March → 30 September
- Marble trout 1 April → 31 October
Related guides
Booking & contacts
Mostnica
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.
Water temperature for Marble Trout
Ideal8.6°Cideal 8–13°C
0°14°28°
How to fish it · for Marble 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
Good — water temperature is right today, though time of day could be better.
Likely species
Mayflies
- Turkey BrownMost likelyLower confidence#14–16 · DunSmall spring dun on slower glides and margins.
- Late March BrownAlso possibleLower confidence#12–14 · DunLate-season upland riffle dun, dusk emergence.
- Iron BlueAlso possibleNearest relative#16–18 · DunCold, grey day — the dun sits long. Good dry-fly water.
Caddisflies
- Green SedgeMost likelyLower confidenceNearest relative#10–12–14–16 · NymphFree-living green caddis larva; fast stony riffles.
- GrannomAlso possibleNearest relative#14–16 · PupaPupa first, then dries as the adults come off.
- Saddle-case CaddisAlso possibleLower confidenceNearest relative#16–18 · AdultTiny blackish caddis; fast riffles, early summer.
Molluscs
- Pond snailsMost likelyLower confidence#10–12–14 · AdultDead-drift or twitch a snail pattern near weed beds.
Oligochaetes
- Aquatic wormsMost likelyLower confidence#12–14–16 · AdultDead-drift a worm pattern deep - a year-round staple.
Hatch timeline · todayQuiet day
Hatch predictions
Today's headline hatch shown — see all 7 active hatches hour by hour as a supporter.
Start free trial14-day free trial. Cancel anytime.
Sub-surface · on the nymphunder the surface
Hatch predictions
Supporters see the full sub-surface read.
Start free trial14-day free trial. Cancel anytime.
Beyond the hatch · worth watchingambient prey(1)
Hatch predictions
Supporters see what else is on the menu.
Start free trial14-day free trial. Cancel anytime.
Evidence
Records-basedModerate confidence
Based on species-occurrence records, not local invertebrate surveys.
Through the year
0–3 scale · October highlighted
J
F
M
A
M
J
J
A
S
O
N
D
Trout seasonSeason
1
2
2
2
2
2
1
Evening SedgeHatch
2
3
3
3
2
Alpine RhithrogenaHatch
1
2
2
1
Large Dark OliveHatch
1
2
2
1
Iron BlueHatch
1
2
2
2
2
2
2
1
Numbers are intensity 0 (none) to 3 (peak) — a guide, not a guarantee.
Ranked for today
Marble 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
Gallery · 2
Mostnica Gorge Terrain map
About this water
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 Marble Trout · confidence 75%
How the 76 is built — score × weight = contribution
Temperature100 × 28%28.0
Flow60 × 22%13.2
Clarity95 × 18%17.1
Feeding Time45 × 13%5.9
Pressure80 × 7%5.6
Insect activity48 × 12%5.8
Conditions total= 76
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
Seasons & zones
- Trout 1 March → 30 September
- Marble trout 1 April → 31 October
Related guides
Booking & contacts
At a glance
Mostnica is a freestone river in Gorenjska / Bohinj (Stara Fužina), Slovenia. Its recorded elevation is about 560 m above sea level and the catchment geology is limestone. The river is described as roughly 6 km long. Our data lists marble trout and brown trout here. The trout season is recorded as running from 1 March to 30 September. The marble trout season is recorded as running from 1 April to 31 October. Best window recorded for anglers: May–September. Core methods listed: Dry fly; Upstream nymph. Level and flow data for this water is linked from 1 gauge. Nearby waters in our listings include Sava Bohinjka at 2.0 km, Savica at 5.0 km and Koritnica (Bača tributary, Rut) at 13 km.