Gammarids
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
Rules at a glance
- Permit required
Water temperature for Grayling
Ideal11°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
Hatch timeline · todayPeak at 12pm
12pm(now) — Autumn Olive
Stage: On emergersApproach: Emerger or dryActivity: 29%
Peak emergence window3 food groups active
Peak activity at 12pm — Autumn Olive (Autumn Olive, Peak emergence window)
Sub-surface · on the nymphunder the surface
Hatch predictions
Top nymph shown — see all 4 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 · November 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
Freshwater ShrimpHatch
2
3
3
3
3
3
3
3
3
3
3
2
Brown SedgeHatch
2
3
3
3
2
Small SpurwingHatch
2
3
3
3
2
Small Dark OliveHatch
2
3
3
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
Permits & access
Permit required — see local rules.
- Croatian fishing licence + local permit.
What's coming
Plan ahead
5-day outlook
Fishing better nearby · 5
Gallery · 2
Mrežnica Terrain map
About this water
Water quality (WFD)
- Ecology: Good
- Chemical: Unknown
WFD classification · HRCSRN0012_004
The full read · show the working · for Grayling · confidence 45%
How the 62 is built — score × weight = contribution
Temperature100 × 28%28.0
Flow55 × 22%12.1
Clarity45 × 18%8.1
Feeding Time15 × 13%2.0
Pressure80 × 7%5.6
Insect activity51 × 12%6.1
Conditions total= 62
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
Mrežnica
Beautiful karst river with tufa barriers and waterfalls.
Water temperature for Grayling
Ideal11°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
Hatch timeline · todayPeak at 12pm
12pm(now) — Autumn Olive
Stage: On emergersApproach: Emerger or dryActivity: 29%
Peak emergence window3 food groups active
Peak activity at 12pm — Autumn Olive (Autumn Olive, Peak emergence window)
Sub-surface · on the nymphunder the surface
Hatch predictions
Top nymph shown — see all 4 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 · November 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
Freshwater ShrimpHatch
2
3
3
3
3
3
3
3
3
3
3
2
Brown SedgeHatch
2
3
3
3
2
Small SpurwingHatch
2
3
3
3
2
Small Dark OliveHatch
2
3
3
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
Permits & access
Permit required — see local rules.
- Croatian fishing licence + local permit.
What's coming
Plan ahead
5-day outlook
Fishing better nearby · 5
Gallery · 2
Mrežnica Terrain map
About this water
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 Grayling · confidence 45%
How the 62 is built — score × weight = contribution
Temperature100 × 28%28.0
Flow55 × 22%12.1
Clarity45 × 18%8.1
Feeding Time15 × 13%2.0
Pressure80 × 7%5.6
Insect activity51 × 12%6.1
Conditions total= 62
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
At a glance
Mrežnica is a limestone river in Karlovačka, Croatia. The catchment geology is recorded as karst, and the water sits at about 211 m above sea level. Species listed for this water: brown trout and grayling. The trout season is recorded as running from 1 March to 30 September. The grayling season is recorded as running from 16 May to 30 November. Best window recorded for anglers: May–August; September–October. Core methods listed: Upstream nymph; Dry fly. Level and flow data for this water is linked from 1 gauge. Its Water Framework Directive ecological status is recorded as good. Nearby waters in our listings include Korana at 12 km, Dobra at 22 km and Vitunjčica at 25 km.