Crystal-clear water with wild brown trout and grayling. The canyon sections offer adventurous fishing in remote surroundings. Part of the Una National Park system.
- Karst
Rules at a glance
- Permit required
Water temperature for Grayling
Ideal9°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
Poor — water temperature is working for you, but water clarity is the limiting factor today. Grayling feeds actively in cold water — peak winter sport.
Hatch timeline · todayPeak at 11am
12pm(now) — Autumn Needle Fly
Stage: Creeping nymphsApproach: Heavy nymphActivity: 43%
Also:Autumn Olive26%
Peak emergence window4 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 4 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 · 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
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
Clear karst rivers with technical dry-fly and nymph fishing. Spring-fed systems like the Ribnik and Pliva demand fine tippets and careful presentation. The Una system adds grayling and huchen diversity.
Hook 14–18 · Fly
in season
Permits & access
Permit required — see local rules.
- Bosnian fishing licence + local permit.
What's coming
Plan ahead
5-day outlook
Fishing better nearby · 5
Gallery · 2
Una_Unac_Confluence Terrain map
About this water
The full read · show the working · for Grayling · confidence 45%
How the 20 is built — score × weight = contribution
Temperature100 × 28%28.0
Flow28 × 22%6.2
Clarity10 × 18%1.8
Feeding Time25 × 13%3.3
Pressure80 × 7%5.6
Insect activity52 × 12%6.2
Limiting factor: Water is unfishable — too coloured for Grayling= 51
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowon-river gaugeobserved
Prey activitymodelled from regional profilemodelled
What would change the calculation
A drop and clear would lift the flow and clarity scores.
The dawn and dusk windows score higher than the midday lull.
Directions
Seasons & zones
- Trout 1 March → 30 September
- Grayling 1 April → 30 November
Related guides
Booking & contacts
Unac
Pristine Una tributary flowing through narrow karst canyon near Martin Brod — one of Bosnia's most unspoilt fly fishing rivers.
Water temperature for Grayling
Ideal9°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
Poor — water temperature is working for you, but water clarity is the limiting factor today. Grayling feeds actively in cold water — peak winter sport.
Hatch timeline · todayPeak at 11am
12pm(now) — Autumn Needle Fly
Stage: Creeping nymphsApproach: Heavy nymphActivity: 43%
Also:Autumn Olive26%
Peak emergence window4 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 4 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 · 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
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
Clear karst rivers with technical dry-fly and nymph fishing. Spring-fed systems like the Ribnik and Pliva demand fine tippets and careful presentation. The Una system adds grayling and huchen diversity.
Hook 14–18 · Fly
in season
Permits & access
Permit required — see local rules.
- Bosnian fishing licence + local permit.
What's coming
Plan ahead
5-day outlook
Fishing better nearby · 5
Gallery · 2
Una_Unac_Confluence Terrain map
About this water
Crystal-clear water with wild brown trout and grayling. The canyon sections offer adventurous fishing in remote surroundings. Part of the Una National Park system.
- Karst
The full read · show the working · for Grayling · confidence 45%
How the 20 is built — score × weight = contribution
Temperature100 × 28%28.0
Flow28 × 22%6.2
Clarity10 × 18%1.8
Feeding Time25 × 13%3.3
Pressure80 × 7%5.6
Insect activity52 × 12%6.2
Limiting factor: Water is unfishable — too coloured for Grayling= 51
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowon-river gaugeobserved
Prey activitymodelled from regional profilemodelled
What would change the calculation
A drop and clear would lift the flow and clarity scores.
The dawn and dusk windows score higher than the midday lull.
Directions
Seasons & zones
- Trout 1 March → 30 September
- Grayling 1 April → 30 November
Related guides
Booking & contacts
At a glance
Unac is a freestone river in Una-Sana Canton / Martin Brod, Bosnia and Herzegovina. The catchment geology is recorded as karst, and the water sits at about 319 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 1 April to 30 November. Best window recorded for anglers: May–August. Core methods listed: Upstream nymph; Dry fly. Nearby waters in our listings include Una at 42 km, Zrmanja at 45 km and Sana at 51 km.