Stoneflies
Caddisflies
Damselflies & dragonflies
Gammarids
Kupa tributary flowing through karst landscape near Ogulin. Wild brown trout and some grayling in the upper reaches. Canyon sections with deeper pools alternate with riffles. Good caddis hatches in spring.
- Karst
Rules at a glance
- Permit required
Water temperature for Grayling
Ideal12°C est.ideal 4–14°C
0°14°28°
How to fish it · for Grayling
When
Midday window — grayling feed best from late morning into early afternoon.
Where
Work runs and glides — grayling shoal in the bottom third of the water column.
Method
Tight-line nymph the bottom third with weighted patterns.
Kit
10 ft #3 rod, floating line, long leader to 4 lb fluoro for nymphs.
Why this works
Good — water temperature is working for you, but time of day is the limiting factor today.
Likely species
Caddisflies
- Green SedgeMost likelyLower confidenceNearest relative#10–12–14–16 · NymphFree-living green caddis larva; fast stony riffles.
- CapererAlso possibleLower confidence#10–12 · AdultBig autumn sedge; fish dry at last light.
- Net-spinning caddisAlso possibleLower confidenceNearest relative#12–14–16 · PupaWidespread riffle net-spinner; evening emergence.
Damselflies & dragonflies
Hatch timeline · todayPeak at 11am
12pm(now) — Autumn Needle Fly
Stage: Creeping nymphsApproach: Heavy nymphActivity: 81%
Also:Autumn Olive52%Reed Smut40%
Peak emergence window10 food groups active
Peak activity at 11am — Autumn Needle Fly (Autumn Needle Fly, 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
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 · September highlighted
J
F
M
A
M
J
J
A
S
O
N
D
Trout seasonSeason
1
2
2
2
2
2
1
Grayling seasonSeason
1
2
2
2
2
2
1
March BrownHatch
2
3
2
Late March BrownHatch
2
3
2
Large Brook DunHatch
2
3
2
Large StoneflyHatch
2
3
2
Numbers are intensity 0 (none) to 3 (peak) — a guide, not a guarantee.
Ranked for today
Grayling 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.
Hook 14–18 · Fly
in season · matches water height
Permits & access
Permit required — see local rules.
- Croatian fishing licence + local permit.
What's coming
Plan ahead
5-day outlook
Other water nearby · 5
Gallery · 2
Terrain map
About this water
Water quality (WFD)
- Ecology: Good
- Chemical: Unknown
WFD classification · HRCSRN0023_003
The full read · show the working · for Grayling · confidence 55%
How the 76 is built — score × weight = contribution
Temperature100 × 28%28.0
Flow80 × 22%17.6
Clarity85 × 18%15.3
Feeding Time10 × 13%1.3
Pressure80 × 7%5.6
Insect activity66 × 12%7.9
Conditions total= 76
Can you trust it?
Water temperatureair-to-water estimateestimated
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
- Grayling 16 May → 30 November
Croatian rules: artificial fly or lure only in permanent grayling habitats. Check concession rules for the specific water.
Prime sport 1 September → 30 November
- 16 May → 30 Nov · Artificial fly or artificial lure
Related guides
Booking & contacts
Dobra
Kupa tributary flowing through karst landscape near Ogulin.
Water temperature for Grayling
Ideal12°C est.ideal 4–14°C
0°14°28°
How to fish it · for Grayling
When
Midday window — grayling feed best from late morning into early afternoon.
Where
Work runs and glides — grayling shoal in the bottom third of the water column.
Method
Tight-line nymph the bottom third with weighted patterns.
Kit
10 ft #3 rod, floating line, long leader to 4 lb fluoro for nymphs.
Why this works
Good — water temperature is working for you, but time of day is the limiting factor today.
Likely species
Caddisflies
- Green SedgeMost likelyLower confidenceNearest relative#10–12–14–16 · NymphFree-living green caddis larva; fast stony riffles.
- CapererAlso possibleLower confidence#10–12 · AdultBig autumn sedge; fish dry at last light.
- Net-spinning caddisAlso possibleLower confidenceNearest relative#12–14–16 · PupaWidespread riffle net-spinner; evening emergence.
Damselflies & dragonflies
Hatch timeline · todayPeak at 11am
12pm(now) — Autumn Needle Fly
Stage: Creeping nymphsApproach: Heavy nymphActivity: 81%
Also:Autumn Olive52%Reed Smut40%
Peak emergence window10 food groups active
Peak activity at 11am — Autumn Needle Fly (Autumn Needle Fly, 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
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 · September highlighted
J
F
M
A
M
J
J
A
S
O
N
D
Trout seasonSeason
1
2
2
2
2
2
1
Grayling seasonSeason
1
2
2
2
2
2
1
March BrownHatch
2
3
2
Late March BrownHatch
2
3
2
Large Brook DunHatch
2
3
2
Large StoneflyHatch
2
3
2
Numbers are intensity 0 (none) to 3 (peak) — a guide, not a guarantee.
Ranked for today
Grayling 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.
Hook 14–18 · Fly
in season · matches water height
Permits & access
Permit required — see local rules.
- Croatian fishing licence + local permit.
What's coming
Plan ahead
5-day outlook
Other water nearby · 5
Gallery · 2
Terrain map
About this water
Kupa tributary flowing through karst landscape near Ogulin. Wild brown trout and some grayling in the upper reaches. Canyon sections with deeper pools alternate with riffles. Good caddis hatches in spring.
- Karst
Water quality (WFD)
- Ecology: Good
- Chemical: Unknown
WFD classification · HRCSRN0023_003
The full read · show the working · for Grayling · confidence 55%
How the 76 is built — score × weight = contribution
Temperature100 × 28%28.0
Flow80 × 22%17.6
Clarity85 × 18%15.3
Feeding Time10 × 13%1.3
Pressure80 × 7%5.6
Insect activity66 × 12%7.9
Conditions total= 76
Can you trust it?
Water temperatureair-to-water estimateestimated
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
- Grayling 16 May → 30 November
Croatian rules: artificial fly or lure only in permanent grayling habitats. Check concession rules for the specific water.
Prime sport 1 September → 30 November
- 16 May → 30 Nov · Artificial fly or artificial lure
Related guides
Booking & contacts