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Flathead River Fishing Report | September 1, 2025

Report by Ryan Stultz
Ryan Stultz guides for Bent Fly Fishing in Montana and reports on the Flathead, Clark Fork, and Blackfoot rivers.
What is working right now

The Flathead River fished well through August into early September 2025 thanks to cool weather and steady rain. Ryan Stultz reports late hopper fishing still working, with mayflies like the Hecuba bringing big fish up. Throw a size 12 or 10 parachute Adams or a Purple Haze to rising fish. The Clark Fork is low but productive, and the Blackfoot is best for wade anglers.

How is the Flathead River fishing right now?

The main stem of the Flathead fished good all through August into early September, with only a few slow days. Cool-downs and light rain kept the fish happy. Ryan Stultz reports strong dry-fly action heading into fall.

What flies are working on the Flathead River?

Late hoppers are still producing, and mayflies like the Hecuba are bringing big fish up. Throw a size 12 or size 10 parachute Adams, or a Purple Haze, or your favorite parachute mayfly pattern to rising fish. These flies are not carried by Catch America.

How do I fish the mayfly hatch on the Flathead?

When you see a few of the big mayflies on the water, the fish look for them. Snip off the big hopper in the second half of the day and throw a parachute mayfly pattern to raise a big fish. You do not need a heavy hatch to get them looking up.

How are the Clark Fork and Blackfoot rivers?

The Clark Fork is low but still putting out lots of good days, best waded. The Blackfoot is very low, around 330 CFS, and too skinny to float, so it is a wade fishery. Go early when it is cool and you will have it almost to yourself.

What is the outlook for Montana fly fishing?

Conditions have been favorable with good weather holding the fish in. Late-season hopper and mayfly action should continue as fall sets in. Water temperatures are holding on the Clark Fork despite low flows.

Watch the full report

From the report (Ryan Stultz): The main stem of the Flathead fished good all through August. We kept getting cool downs, little rain here, just making for happy fish. Hoppers still working, which is awesome. We saw the first appearance of the Hecuba pop out last week. A size 12 parachute Adams or even a size 10 parachute Adams would work great, or Purple Haze would do the trick too.

Flathead River September 1, 2025 FAQ

Are hoppers still working on the Flathead River?

Yes, late hopper fishing is still producing into early September, per Ryan Stultz.

What mayfly is hatching on the Flathead?

The Hecuba, a large mayfly the fish go crazy over.

What dry flies should I use on the Flathead?

A size 12 or 10 parachute Adams, a Purple Haze, or your favorite parachute mayfly pattern.

Can you float the Blackfoot River right now?

No. At around 330 CFS it is too low to get a boat through, so it is a wade fishery.

How is the Clark Fork fishing?

Low but productive, with good days for wade fishermen and water temps holding.

When is the best time to fish the Blackfoot?

Early in the day when it is cool, with hardly anyone around.

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