- Ecology: Bad
Rules at a glance
- Licence required
Water temperature for Rainbow Trout
Warm — slow23°C est.ideal 10–18°C
0°14°28°
How to fish it · for Rainbow 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 22.5°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 8 active hatches hour by hour with Pro.
Start free trial14-day free trial. Cancel anytime.
Sub-surface · on the nymphunder the surface
Hatch predictions
See the full sub-surface read 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
Survey-backed · regionalModerate confidence
Backed by regional invertebrate surveys; no sampling on this exact reach 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
1
Grayling seasonSeason
1
2
2
2
2
1
GrannomHatch
2
2
Evening SedgeHatch
2
3
3
3
2
Large Dark OliveHatch
1
2
2
1
Iron BlueHatch
1
2
2
1
Numbers are intensity 0 (none) to 3 (peak) — a guide, not a guarantee.
Ranked for today
Rainbow Trout fly box
Permits & access
Permit required — see local rules.
- State licence (rybářský lístek) + local permit from ČRS branch
- Fly-only, barbless hooks mandatory
- Brown trout protected Sep 1–Apr 15
- Grayling protected Dec 1–Jun 15.
What's coming
Plan ahead
5-day outlook
Cooler water nearby · 1
Probably above the Rainbow Trout safety line — these are likely cooler, but carry a thermometer.
Gallery · 2
Vltava 28 Terrain map
Water quality (WFD)
The full read · show the working · for Rainbow Trout · confidence 90%
How the 12 is built — score × weight = contribution
Temperature6 × 28%1.7
Flow60 × 22%13.2
Clarity85 × 18%15.3
Feeding Time85 × 13%11.1
Pressure75 × 7%5.3
Insect activity61 × 12%7.3
Limiting factor: Water temperature (22.5°C) is outside Rainbow Trout's preferred range (10–18°C)= 54
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowon-river gaugeobserved
Prey activitysurvey-backed invertebrate datasurvey
What would change the calculation
Cooler water — back toward the 10–18 °C ideal band — would lift the score and ease welfare.
Directions
Seasons & zones
- Rainbow trout 16 April → 31 August
- Trout 16 April → 31 August
- Grayling 16 June → 30 November
Czech national rule: grayling (lipan podhorní) protected 1 December – 15 June. Open window is 16 June – 30 November. Czech Anglers Union (ČRS) salmonid fisheries also have method and access rules — check the local ČRS district permit for specific conditions.
Closed in spring for spawning.
Prime sport 1 September → 30 November
Related guides
Booking & contacts
Vltava 28
Water temperature for Rainbow Trout
Warm — slow23°C est.ideal 10–18°C
0°14°28°
How to fish it · for Rainbow 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 22.5°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 8 active hatches hour by hour with Pro.
Start free trial14-day free trial. Cancel anytime.
Sub-surface · on the nymphunder the surface
Hatch predictions
See the full sub-surface read 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
Survey-backed · regionalModerate confidence
Backed by regional invertebrate surveys; no sampling on this exact reach 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
1
Grayling seasonSeason
1
2
2
2
2
1
GrannomHatch
2
2
Evening SedgeHatch
2
3
3
3
2
Large Dark OliveHatch
1
2
2
1
Iron BlueHatch
1
2
2
1
Numbers are intensity 0 (none) to 3 (peak) — a guide, not a guarantee.
Ranked for today
Rainbow Trout fly box
Permits & access
Permit required — see local rules.
- State licence (rybářský lístek) + local permit from ČRS branch
- Fly-only, barbless hooks mandatory
- Brown trout protected Sep 1–Apr 15
- Grayling protected Dec 1–Jun 15.
What's coming
Plan ahead
5-day outlook
Cooler water nearby · 1
Probably above the Rainbow Trout safety line — these are likely cooler, but carry a thermometer.
Gallery · 2
Vltava 28 Terrain map
Water quality (WFD)
- Ecology: Bad
The full read · show the working · for Rainbow Trout · confidence 90%
How the 12 is built — score × weight = contribution
Temperature6 × 28%1.7
Flow60 × 22%13.2
Clarity85 × 18%15.3
Feeding Time85 × 13%11.1
Pressure75 × 7%5.3
Insect activity61 × 12%7.3
Limiting factor: Water temperature (22.5°C) is outside Rainbow Trout's preferred range (10–18°C)= 54
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowon-river gaugeobserved
Prey activitysurvey-backed invertebrate datasurvey
What would change the calculation
Cooler water — back toward the 10–18 °C ideal band — would lift the score and ease welfare.
Directions
Seasons & zones
- Rainbow trout 16 April → 31 August
- Trout 16 April → 31 August
- Grayling 16 June → 30 November
Czech national rule: grayling (lipan podhorní) protected 1 December – 15 June. Open window is 16 June – 30 November. Czech Anglers Union (ČRS) salmonid fisheries also have method and access rules — check the local ČRS district permit for specific conditions.
Closed in spring for spawning.
Prime sport 1 September → 30 November
Related guides
Booking & contacts