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 temperature for Brown Trout
Warm — slow22°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
Water at 22°C. This is the line where catch-and-release kills brown trout. Do not fish for them today.
Hatch timeline · todayPeak at 6pm
Hatch predictions
Today's headline hatch shown — see all 3 active hatches hour by hour with Pro.
Start free trial14-day free trial. Cancel anytime.
Beyond the hatch · worth watchingambient prey
Hatch predictions
Top prey shown — see all 2 with Pro.
Start free trial14-day free trial. Cancel anytime.
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
Grayling seasonSeason
1
2
2
2
2
2
1
March BrownHatch
2
3
2
Large StoneflyHatch
2
3
2
Olive UprightHatch
2
3
3
2
Alpine RhithrogenaHatch
2
3
3
2
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.
- Croatian fishing licence + local permit.
What's coming
Plan ahead
5-day outlook
Water here around 22°C. Nothing cooler within range — carry a thermometer.
About this water
Water quality (WFD)
- Ecology: Good
- Chemical: Unknown
WFD classification · HRCSRN0023_003
The full read · show the working · for Brown Trout · confidence 90%
How the 12 is built — score × weight = contribution
Temperature6 × 28%1.7
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time65 × 13%8.5
Pressure80 × 7%5.6
Insect activity67 × 12%8.0
Limiting factor: Water temperature (22°C) is outside Brown Trout's preferred range (10–16°C)= 59
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowon-river gaugeobserved
Prey activitymodelled from regional profilemodelled
What would change the calculation
Cooler water — back toward the 10–16 °C ideal band — would lift the score and ease welfare.
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 Brown Trout
Warm — slow22°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
Water at 22°C. This is the line where catch-and-release kills brown trout. Do not fish for them today.
Hatch timeline · todayPeak at 6pm
Hatch predictions
Today's headline hatch shown — see all 3 active hatches hour by hour with Pro.
Start free trial14-day free trial. Cancel anytime.
Beyond the hatch · worth watchingambient prey
Hatch predictions
Top prey shown — see all 2 with Pro.
Start free trial14-day free trial. Cancel anytime.
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
Grayling seasonSeason
1
2
2
2
2
2
1
March BrownHatch
2
3
2
Large StoneflyHatch
2
3
2
Olive UprightHatch
2
3
3
2
Alpine RhithrogenaHatch
2
3
3
2
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.
- Croatian fishing licence + local permit.
What's coming
Plan ahead
5-day outlook
Water here around 22°C. Nothing cooler within range — carry a thermometer.
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 Brown Trout · confidence 90%
How the 12 is built — score × weight = contribution
Temperature6 × 28%1.7
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time65 × 13%8.5
Pressure80 × 7%5.6
Insect activity67 × 12%8.0
Limiting factor: Water temperature (22°C) is outside Brown Trout's preferred range (10–16°C)= 59
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowon-river gaugeobserved
Prey activitymodelled from regional profilemodelled
What would change the calculation
Cooler water — back toward the 10–16 °C ideal band — would lift the score and ease welfare.
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