Still Waters
STILL WATERS
ReportAUG 4 — 11, 2026
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Flow
—CFS
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Water Temp
—
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Weather
41–79°F
Areas Of Smoke
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Reported By
Bruce Staples
On the water
Irrigation reservoirs are fishing best at the bookends of the day with light winds and sunny skies in the forecast. Anglers should be aware that blue-green algae is spreading in Island Park Reservoir.
From the ShopBruce Staples · August 4, 2026
Early and late in the day remain the best times to fly fish irrigation reservoirs. Life cycle patterns for speckled dun mayflies, damsel flies, and scud patterns will produce around submerged weed beds early in the day.
Blue-green algae are spreading in Island Park Reservoir.
What's Working — Hot Flies
Hatch Chart
| Insect | Size | Activity | Prime Time |
|---|---|---|---|
| Speckled Dun Mayfly | #12–16 | Active — fish life cycle patterns (nymph through emerger) | Early morning & evening |
| Damselfly | #10–14 | Active — fish life cycle patterns near weed beds | Early morning & evening |
| Scud | #12–16 | Consistent — fish around submerged weed beds | Early morning |
Best Time Window
- EARLY MORNING (first light to ~9 AM): Prime window — work life cycle patterns for speckled dun mayflies, damselflies, and scud around submerged weed beds
- EVENING (2 hours before dark to last light): Second prime window — return to the weed beds with the same life cycle and scud patterns as fish feed aggressively before dark
Guide's Tip
From the benchThe staffer specifically calls for life cycle patterns — meaning nymph, emerger, and adult stages — for both speckled dun mayflies and damselflies, so carry multiple stages of each and be ready to switch. Swing by the shop and ask which specific damsel nymph and scud patterns we're stocking for Island Park-area reservoirs right now. If you're heading to Island Park Reservoir, check current conditions before launching — blue-green algae is actively spreading there and can pose health risks to people and pets.
Main Species
Rainbow Trout
Brook Trout
Yellowstone Cutthroat Trout
