- Blackfly larvae/pupaeMost likelyLower confidence#16–18–20 · PupaSmall dark soft-hackle drifted through riffle seams.
- Riffle beetles (US)Most likelyLower confidence#16–18–20 · NymphSmall riffle beetle; larva and adult, clean riffles.
- Diving beetlesAlso possibleLower confidence#8–10–12 · AdultTwitch a beetle pattern along weedy edges at dusk.
- Aquatic wormsMost likelyLower confidence#12–14–16 · AdultDead-drift a worm pattern deep - a year-round staple.
Hatch predictions
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Beyond the hatch · worth watchingambient prey(1)
Hatch predictions
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Based on species-occurrence records, not local invertebrate surveys.
Numbers are intensity 0 (none) to 3 (peak) — a guide, not a guarantee.
- All year, barbless artificial lures, 0 trout, Cogswell Dam to the second bridge above Highway 39
- California licence.
Rainbow trout; whether they are wild or hatchery-derived is not established by CDFW. The West Fork is not on CDFW's designated Wild or Heritage Trout list — its catch-and-release status comes from the special regulations only.
The full read · show the working · for Rainbow Trout · confidence 90%
- Trout 1 January → 31 December
West Fork San Gabriel River (catch-and-release reach)

- Blackfly larvae/pupaeMost likelyLower confidence#16–18–20 · PupaSmall dark soft-hackle drifted through riffle seams.
- Riffle beetles (US)Most likelyLower confidence#16–18–20 · NymphSmall riffle beetle; larva and adult, clean riffles.
- Diving beetlesAlso possibleLower confidence#8–10–12 · AdultTwitch a beetle pattern along weedy edges at dusk.
- Aquatic wormsMost likelyLower confidence#12–14–16 · AdultDead-drift a worm pattern deep - a year-round staple.
Hatch predictions
Today's headline hatch shown — see all 6 active hatches hour by hour as a supporter.
Start free trial14-day free trial. Cancel anytime.
Hatch predictions
Top nymph shown — see all 3 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.
Based on species-occurrence records, not local invertebrate surveys.
Numbers are intensity 0 (none) to 3 (peak) — a guide, not a guarantee.
- All year, barbless artificial lures, 0 trout, Cogswell Dam to the second bridge above Highway 39
- California licence.
Rainbow trout; whether they are wild or hatchery-derived is not established by CDFW. The West Fork is not on CDFW's designated Wild or Heritage Trout list — its catch-and-release status comes from the special regulations only.
The full read · show the working · for Rainbow Trout · confidence 90%
- Trout 1 January → 31 December