Rules at a glance
- Free fishing
- Fly only
- Barbless
Water temperature for Brown Trout
Cool — slow10°C est.ideal 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
Good — water temperature is working for you, but time of day is the limiting factor today.
Likely species
Mayflies
Mayflies- Turkey BrownMost likelyLower confidence#14–16 · DunSmall spring dun on slower glides and margins.
- Ephemera vulgata (lake mayfly)Also possibleLower confidenceNearest relative#8–10–12 · NymphLarge lake/slow-river mayfly; burrows soft sediment.
- 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
Caddisflies- Green SedgeMost likelyLower confidenceNearest relative#10–12–14–16 · NymphFree-living green caddis larva; fast stony riffles.
- Net-spinning caddis (S. Europe)Also possibleLower confidenceNearest relative#12–14–16 · PupaWidespread riffle net-spinner; evening emergence.
- Stone-case caddisAlso possibleLower confidenceNearest relative#14–16–18 · NymphTiny stone-cased larva; clean gravel riffles.
- GrannomAlso possibleNearest relative#14–16 · PupaPupa first, then dries as the adults come off.
Stoneflies
Stoneflies- Little Brown StoneMost likelyLower confidence#16–18 · AdultSmall dark stone nymph or adult in early spring.
- NeedleflyAlso possibleLower confidenceNearest relative#16–18 · AdultSmall slender stonefly; clean, cold headwater riffles.
Damselflies & dragonflies
Damselflies & dragonflies- Migrant HawkerMost likelyLower confidence#6–8 · NymphStrip a big hawker nymph erratically near cover.
- DamselfliesAlso possibleNearest relative#10–12 · NymphSlow-retrieve a damsel nymph along the weed edges.
Hatch timeline · todayPeak at 10h
12h(now) — Black Midge
Stage: On emergersApproach: Emerger or dryActivity: 72%
Also:Iron Blue43%Autumn Needle Fly41%Heather Fly31%
Peak emergence window11 food groups active
Peak activity at 10h — Black Midge (Black Midge, Peak emergence window)
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 2 as a supporter.
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 · September 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
Fly box · Brown Trout
Top
6-10 · Pattern
High-confidence seasonal pick
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
The full read · show the working · for Brown Trout · confidence 75%
How the 79 is built — score × weight = contribution
Temperature98 × 28%27.4
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time40 × 13%5.2
Pressure80 × 7%5.6
Insect activity51 × 12%6.1
Conditions total= 79
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
Water temperature for Brown Trout
Cool — slow10°C est.ideal 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
Good — water temperature is working for you, but time of day is the limiting factor today.
Likely species
Mayflies
- Turkey BrownMost likelyLower confidence#14–16 · DunSmall spring dun on slower glides and margins.
- Ephemera vulgata (lake mayfly)Also possibleLower confidenceNearest relative#8–10–12 · NymphLarge lake/slow-river mayfly; burrows soft sediment.
- 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.
- Net-spinning caddis (S. Europe)Also possibleLower confidenceNearest relative#12–14–16 · PupaWidespread riffle net-spinner; evening emergence.
- Stone-case caddisAlso possibleLower confidenceNearest relative#14–16–18 · NymphTiny stone-cased larva; clean gravel riffles.
- GrannomAlso possibleNearest relative#14–16 · PupaPupa first, then dries as the adults come off.
Stoneflies
- Little Brown StoneMost likelyLower confidence#16–18 · AdultSmall dark stone nymph or adult in early spring.
- NeedleflyAlso possibleLower confidenceNearest relative#16–18 · AdultSmall slender stonefly; clean, cold headwater riffles.
Damselflies & dragonflies
- Migrant HawkerMost likelyLower confidence#6–8 · NymphStrip a big hawker nymph erratically near cover.
- DamselfliesAlso possibleNearest relative#10–12 · NymphSlow-retrieve a damsel nymph along the weed edges.
Hatch timeline · todayPeak at 10h
12h(now) — Black Midge
Stage: On emergersApproach: Emerger or dryActivity: 72%
Also:Iron Blue43%Autumn Needle Fly41%Heather Fly31%
Peak emergence window11 food groups active
Peak activity at 10h — Black Midge (Black Midge, Peak emergence window)
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 2 as a supporter.
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 · September 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
Fly box · Brown Trout
Top
6-10 · Pattern
High-confidence seasonal pick
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
The full read · show the working · for Brown Trout · confidence 75%
How the 79 is built — score × weight = contribution
Temperature98 × 28%27.4
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time40 × 13%5.2
Pressure80 × 7%5.6
Insect activity51 × 12%6.1
Conditions total= 79
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