Montana ·
Bighorn River Fly Fishing Report - April 4/12/2026
BIGHORN RIVER FLY FISHING REPORT
Yellowtail Dam to Fort Smith (MT) — Tailwater trout tactics
Report Date: April 12, 2026 | Next Update: April 19, 2026
Current River Conditions (at a glance)
Early spring tailwater conditions favor cold-water techniques. Expect heavy midge activity in low-light periods and Baetis (BWO) windows midday. Focus on deep nymph presentations and slow, deliberate streamer work in the afternoons. Avoid summer terrestrials or large stonefly offerings — they're out-of-season.
Flows & Clarity
Typical tailwater releases from Yellowtail Dam keep the Bighorn fishable through spring.
Flow Rate (typical tailwater range): 2,500–4,000 CFS (variable by dam schedule)
Water Clarity: Clear to lightly stained — excellent sight fishing in many runs
Typical tailwater releases from Yellowtail Dam keep the Bighorn fishable through spring.
Flow Rate (typical tailwater range): 2,500–4,000 CFS (variable by dam schedule)
Water Clarity: Clear to lightly stained — excellent sight fishing in many runs
Water Temperature
Current: ~40–44°F (4–7°C) — cold, trout are responsive but slow to chase
Daily Range: 38–46°F as air warms; cold mornings, modest afternoon rise
Current: ~40–44°F (4–7°C) — cold, trout are responsive but slow to chase
Daily Range: 38–46°F as air warms; cold mornings, modest afternoon rise
Weather
Forecast: Cool spring days with sun and light wind; chance of a late-season shower or snow at higher elevations
Best windows: mid-morning through mid-afternoon for Baetis activity; low-light (dawn/dusk) for midge and streamer takes
Forecast: Cool spring days with sun and light wind; chance of a late-season shower or snow at higher elevations
Best windows: mid-morning through mid-afternoon for Baetis activity; low-light (dawn/dusk) for midge and streamer takes
Access & Regulations
Main public access points (Yellowtail/Barry’s Landing/Fort Smith) open. Road conditions: typical early‑spring gravel and dirt spots may be soft—check local BLM/County sources.
Regulations: Confirm current limits and any special regs (seasonal closures, bait restrictions, fly-fishing-only sections) with Montana Fish, Wildlife & Parks before you go: https://fwp.mt.gov
Main public access points (Yellowtail/Barry’s Landing/Fort Smith) open. Road conditions: typical early‑spring gravel and dirt spots may be soft—check local BLM/County sources.
Regulations: Confirm current limits and any special regs (seasonal closures, bait restrictions, fly-fishing-only sections) with Montana Fish, Wildlife & Parks before you go: https://fwp.mt.gov
Hatch & Surface Activity — what to expect (April)
| Insect / Stage | Size | Activity Level | Prime Time |
|---|---|---|---|
| Midges (all stages) | #18–24 | High — earliest and most consistent food source (dawn/dusk and overcast) | Dawn, dusk, cloudy periods |
| BWO / Baetis (emerger & spinner) | #18–22 | Light → moderate — short midday windows when water warms slightly | Late morning to mid-afternoon (watch seams) |
| PMD / small mayflies | #16–20 | Light — isolated events possible | Midday (if water warms) |
| Streamers / subsurface bait | 2–6 (streamer sizes) | Always effective when fish are holding deep or aggressive during low-light | Low light, quick pulls through deep seams/holes |
Recommended Flies (seasonally appropriate)
All pattern links come from our fly database — I've prioritized flies suitable for mid‑April cold-water tactics (deep nymphing, midge/BWO, slow streamers). Sizes shown are typical for the Bighorn at this time of year.
Nymphs / Euro / Jigged (deep presentations)
- Egan's Thread Frenchie Jig - Olive (jigged nymph; tungsten jig; sizes ~12) — dead-slow near bottom, great as point fly.
- Pheasant Tail Tungsten (classic PTN; sizes 18–20 or larger jig size for deeper water)
- Roza's World Spain Perdigon - Barbless (perdigon style for tight columns; sizes 18–22)
- Egan's Frenchie (tungsten/beadhead attraction nymph; versatile anchor/dropper)
Midges & Small Nymphs (indicator / euro setups)
- Black Zebra Midge (TBH) — sizes #18–24 for slow, subtle takes.
- Black Mirage Zebra Midge — great tungsten or jig versions for deeper feeding lanes.
- Top Secret Midge — match midge clusters, small sizes #18–22.
- Jujubee Midge - Zebra — indicator-friendly, highly effective in early spring
BWO / Baetis & Emergers (sight / surface opportunities)
- Parachute - Blue Wing Olive (BWO) — reliable surface imitation when Baetis are present (#20–22).
- Stealth Link Mercer - PMD — excellent emerger/dun option when small mayflies appear.
- Barr's Flashback Emerger - BWO — use when fish key on emergers.
- Egan's Silver Bullet - Baetis — great as a dropper or indicator nymph in Baetis windows.
Streamers & Subsurface 'big food' (slow strip / dead‑drift)
- Coffey's CH Sparkle Minnow Sculpin — slow strips along structure; use sizes #4–6.
- Sculpzilla - Olive — articulated and single-jointed sculpin imitations; excellent in deep runs.
- Galloup's Slick Willy - Whitefish — baitfish profile for aggressive trout in low light.
- Near Nuff Sculpin - Olive — classic sculpin that triggers follows; fish slowly.
Soft-hackles / emergers / attractor nymphs
- Soft Hackle Pheasant Tail Jig - Barbless — lively near‑bottom presentation that reads well.
- CDC Soft Hackle Tailwater Sowbug Jig - Rainbow — soft‑hackle action with nymph profile.
- Duracell Bomb - Pheasant Tail — compact, buggy attractor good as a point fly.
- Flashback Pheasant Tail — emerger/soft‑hackle hybrid for selective feeding trout.
Tactics — cold-water game plan
Focus: nymph deeply, fish tiny midge presentations in low light, and use slow, deliberate streamer work when fish are inactive but holding on structure.
- Deep Nymphing / Euro: run a heavy, short‑leader tungsten jig (size 12–16) as the point fly with a soft‑hackle or PT droppers. Keep the rig tight, contact with the bottom, short hops across seams and pocket water. Use size ranges from 14 (stone/bug imitations) down to 20–24 for midge impostors depending on visibility.
- Indicator / Two‑fly: use an indicator 5–7' above a 1–2X tippet — midge/nymph combos work well. Swap to a smaller midge or BWO emerger when surface activity picks up.
- Midge game: in mornings and evenings downsize to #18–24 black/olive midges. Dead‑drift long and slow in tailouts, along foam lines and behind boulders where fish concentrate. Small, high‑quality tungsten jigged midges will outproduce bulky attractors in cold water.
- Slow streamer: strip very slowly with pauses through deep runs and holes. Target flats just below current seams, near large boulders and long pocket water. Fish streamers on sink‑tips or heavier rods (6–8 weight) in low light; in cold water, trout often take on the drop or on long pauses rather than a fast strip.
- Where to fish: pick seams and tails of runs during the day (nymphing), deep holes and cut banks for slow streamer work, and low‑gradient tailouts for midge activity. Watch edges of foam lines for Baetis rises midday.
- Deep Nymphing / Euro: run a heavy, short‑leader tungsten jig (size 12–16) as the point fly with a soft‑hackle or PT droppers. Keep the rig tight, contact with the bottom, short hops across seams and pocket water. Use size ranges from 14 (stone/bug imitations) down to 20–24 for midge impostors depending on visibility.
- Indicator / Two‑fly: use an indicator 5–7' above a 1–2X tippet — midge/nymph combos work well. Swap to a smaller midge or BWO emerger when surface activity picks up.
- Midge game: in mornings and evenings downsize to #18–24 black/olive midges. Dead‑drift long and slow in tailouts, along foam lines and behind boulders where fish concentrate. Small, high‑quality tungsten jigged midges will outproduce bulky attractors in cold water.
- Slow streamer: strip very slowly with pauses through deep runs and holes. Target flats just below current seams, near large boulders and long pocket water. Fish streamers on sink‑tips or heavier rods (6–8 weight) in low light; in cold water, trout often take on the drop or on long pauses rather than a fast strip.
- Where to fish: pick seams and tails of runs during the day (nymphing), deep holes and cut banks for slow streamer work, and low‑gradient tailouts for midge activity. Watch edges of foam lines for Baetis rises midday.
Quick rigs & setup suggestions
- Euro setup: short leader with a tungsten jigged point (size 12–16) and a smaller beaded dropper (PT, Perdigon) 12–18" behind; use 0X–2X depending on water clarity.
- Indicator rig: 9–12' leaders with a clear indicator; point fly tungsten jig (12–14), dropper a small midge or PT (18–22).
- Streamer rig: 6–8 wt, sink‑tip line or heavy intermediate; 12–18" bite leader of 20–25 lb braid‑to‑mono; slow strip/pause cadence.
- Tippet: 4–6X for midges/BWO dries/emitgers; 2–4X for nymphs/streamers as needed.
Notes on regulations & safety
Always verify current regulations before fishing. This report does not replace official closures, seasonal special regulations (fly‑fishing only, bait restrictions, or emergency closures) or private‑land access rules. Check Montana Fish, Wildlife & Parks for Bighorn River rules and any last‑minute closures: https://fwp.mt.gov.
