Limestone · Karst · Karlovačka

Mrežnica

Photo of Mrežnica

Beautiful karst river with tufa barriers and waterfalls.

Marginal · Brown Trout
Elk Hair Caddis · 12-16
Marginallive now
Slow going — pick your moments
River temperature is the limiting factor today, not the flow. Fish dawn or dusk if you go at all, and handle everything with extra care.
90% confidence
What moved it
  • Level0.27 mDropping after lift
  • Water temp18.0°C
  • ClarityClear
Today's fly
Elk Hair Caddis
Elk Hair Caddis12-16
High-confidence seasonal pick
Conditions on the water
Live gauge
Level
Steady
0.27 m
Dropping after lift
Water temp18.0°C
ClarityClear
Weather28°C
WindNE 9 km/h
Pressure1024 hPa
Rain · recent0.0 mm
Rain · ahead0.0 mm

The nearest gauge doesn't record temperatures, so we've estimated it — defer to the river keeper's advice.

Water temperature for Brown Trout
Warm — slow
18°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 18°C — above the brown trout caution line (18°C). Fish dawn or dusk only. Land it fast, wet hands, no air shots.
Hatch timeline · todayQuiet day

Hatch predictions

Today's headline hatch shown — see all 5 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 2 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
Grayling seasonSeason
1
2
2
2
2
2
1
Brown SedgeHatch
2
3
2
Freshwater ShrimpHatch
2
3
3
3
3
3
3
3
3
3
3
2
Blue Winged OliveHatch
2
3
3
3
3
2
Mayfly (Green Drake)Hatch
2
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 18°C. Nothing cooler within range — carry a thermometer.
Gallery · 2
  1. Photo of Mrežnica
    Mrežnica
  2. Terrain map of the venue
    Terrain map
About this water

Beautiful karst river with tufa barriers and waterfalls. Wild brown trout in clear pools between travertine cascades. The tufa character creates unique habitat — slow glides above barriers, faster runs below. An unusual and visually stunning fishery.

  • Karst
Water quality (WFD)
  • Ecology: Good
  • Chemical: Unknown

WFD classification · HRCSRN0012_004

The full read · show the working · for Brown Trout · confidence 90%
How the 40 is built — score × weight = contribution
Temperature56 × 28%15.7
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time65 × 13%8.5
Pressure80 × 7%5.6
Insect activity63 × 12%7.6
Conditions total= 72
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
Apple MapsGoogle Maps
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
Grayling Playbookgrayling tacticsEuro Nymphingsubsurface methods
Booking & contacts