When do Brook Trout Spawn

When do Brook Trout Spawn (Get the Timing Right!)

There is nothing nicer than to be able to cast a small dry to an unsuspecting brookie on a small stream.

The sheer beauty of their environment is enough to get me out casting a fly.  When you lift a beautiful brook trout out of the water revealing the white-tipped fins and marbled backs.   

As with all fish species, the spawning period is an important time of the year, and this is a time when we should give the fish the respect and time they need to carry out this task. As anglers, it’s up to us to manage and preserve the future of our relevant fisheries.

So as we all know, different fish species spawn at different times of the year. What is more interesting is that different salmonids species spawn at different times, rainbows in spring and browns in the fall.

So when do brookies spawn?

Brook trout spawn in the fall for the northern hemisphere. Usually between late September and November, the exact date depends on water temperature and stream flow. In Michigan I’ve seen spawning brook trout in November (source). While in the Smokie Mountains plan for early October (source).

What Time of Year Do Brook Trout Spawn?

Salvelinus fontinalis, their name suggests; Salvelinus- small salmon, fontinalis- Living in streams. Brookies love the smaller gin-clear headwaters and side tributaries.

The spawning time for brooks is anywhere between late September and November each year, and this fall period is vital for the brook trout to settle and get things done.

Guide Tip: Sometimes brook trout can be a little picky. Learn some of my tips and tricks in the complete guide -> How to Fly Fish for Brook Trout

The fish look for sandy or gravely bottoms that will have an excellent high, oxygenated flow of spring-fed water. The water temperature is key to the development of the trout eggs into alevins.

Factors that Affect Brook Trout Spawning


Water temperature plays a vital role in the exact time the brookies spawn and the speed at which the eggs and alevins develop. The water needs to stay at a constant temperature range, and ideally, 42-45°F (6-7°C) is what is required for the above to happen smoothly. What’s more, this temperature needs to stay constant without much variety.

Stream Flow

Stream or current flow plays its part as well. The cool running water provides the much-needed oxygen over the nest and eggs, allowing them to grow. This flow is also important for the development of alevin and fingerlings into fry.

River Bottom

A sandy, gravel bottom is what brookies love to make their ‘REDD’ in. This type of river bottom will change slightly from species to species, but the justs of it stays the same. The female makes an area suitable for her eggs to be laid, and the male will swim over it and fertilize that area. Together they guard this for a while or until the eggs are hatched.

Oxygen Level

Highly oxygenated water is crucial for the development and growth of brook trout eggs and alevins. The oxygen needs to stay constant with the cool water constantly flowing over the REDD to ensure a productive nest.

How to Fish for Brook Trout During the Spawning Season

Whether to fish in the pre-spawn or during the spawn is closely debated. They both have varied opinions and truths. I am of the belief that a very early pre-spawn fishing mission is great, and you can end up having great days fishing catching some both aggressive and beautiful brookies.

Before the Spawn

Before the spawn can be a very productive time to target brookies, the fish are more aggressive and tend to eat at will, provided you get the right drift or good swing with the fly.

Another great way to enjoy a pre-spawn mission is to target the species that would otherwise naturally feed on the species that will start to spawn. Rainbow trout are the first inline when it comes to feeding on brook trout eggs. The bows will hang off downstream and freely pick off eggs and alevins washed downstream.

These fish can be fished with the normal methods with the use of brighter flies. You will find that at this time of the year, the fish are triggered with brighter colors. I love using chartreuse, coral pink, and hot spot orange.

I like to tie my streamer patterns with these colors in the tails, or for smaller triggers, I tie the collars in these colors with a light CDC hackle.

Guide Tip: You might ask how big a brook trout can get? Can you image a 14 pound brook trout? Read about more record brook trout and places to catch them in this article. -> The Biggest Brook Trout Ever Caught (with Maps and Tips)

During the Spawn

Fishing during the spawn is not recommended, in my opinion. As fly fishers, it’s up to us to preserve the waters we fish and the species we target. My thoughts are that there are many other species to target when brookies are in spawn.

Rainbows are a great example as they spawn in the spring and are a great target species when the brooks and browns are spawning.

But when we talk about targeting spawning fish, it’s a big no-no for me. Let them do their thing and focus on other species. It is as simple as that!

Guide Recommendation: What flies should be in your fly box? Be about my favorites in -> The Best Flies for Brook Trout

Should You Target Spawning Brook Trout?

There are many thoughts and opinions regarding whether we should or shouldn’t fish for spawning fish. In my mind, we are to let them do their thing.

There are plenty of other species to chase during this fall spawn. The rainbows will be very active and aggressive at this time, and sure you may not find them in the same small stream, but it is worth going out to find some bows at this time.

If you are like me and target many species of fish on fly, then autumn bass is great fun as well. They will be fattening themselves up for the winter and are awesome to target on the fly.

What is a Redd, and What’s it Look Like?

A Redd is an oval, concaved patch of rocks that the brook trout clean and arranges in order for the eggs to be laid and fertilized. The shape may change slightly from species to species, but all redds have the same purpose.

The hen and cock fish will both spend time at the redd during this whole process. A redd is easily recognizable in the shallow river tributaries and side streams by seeing a cleaner patch of gravely river bottom.

I recommend that you take a walk up river during the spawn to see the redds and where they will be. Once the fertilization and hatching are done, the trout tend to move off back into the main current. The alevin is left to grow before they head out into the big world.

The issue comes in with anglers when they can’t see the nice clean, very distinctive redd post the spawn. The redd gets covered by the usual river silt etc. and identifying it is nearly impossible. So when we arrive ready to fish in early spring, anglers will walk straight through the nesting areas without even knowing it.

In my mind, it’s pointless, dong all the hard work preserving the fish in the spawn and then not taking care of the hatchlings after either.

Guide Pro Tip:  As a guide and angler who takes a lot of pride and enjoyment from seeing the local waters kept clean and as healthy as possible, I always suggest that we mark the redds out from the bank and with a GPS for this exact reason.

Will Brook Trout Die After Spawning?

This is a common misconception. The short answer is no! Trout species don’t naturally die after they spawn, and it is only when they have their energy levels depleted that they cant fend for themselves.

It is only the salmon species that die naturally after the spawn.

When do Brook trout spawn?

When in Montana?

Brook trout were introduced into the area in the late 1800s and have made their home in the cooler headwaters.

Each year, they spawn September – October, with the eggs being laid and fertilized in the redd. The fry then emerge towards February end. The fry will hug the banks and stay out of sight until they are large enough to feed and swim around.

Guide Tip: Maybe you’ve heard this. “Teach a man to fish and he’ll never go hungry, teach a man to fly fish and he’ll move to Montana.” Looking for the best rivers and lakes in Montana? Read about The Best Places to Fly Fish in Montana.

When in Colorado?

The brookies spawn at the same time as the brown trout in Colorado. When the water drops to the correct temperature, late September, fall is the best time.

As the seasons change and it gets cooler, the leaves start to change to that golden, rusty amber. This is when you know it’s time to target the big bow and some bass.

For more info on Colorado fly fishing read our article on Where to Fly Fish in Colorado

When in Wyoming?

Wyoming is spoiled for choice in my mind. With the Brookies and browns spawning in the fall and rainbows and cutthroats spawning in the spring, there is no reason why the fish can’t be left to spawn in peace with so many other species to offer.

Guide Tip: As mentioned earlier, spawning brook trout can “turn-on” other fish. The best option is to target the species that would feed brook trout when other fish are spawning. For more information on this, please check out Where to Fly Fish in Wyoming.

When in Michigan?

It is a little later in the year but October/ November are the months for the brookies spawn in Michigan.

The temperature needs to start cooling down for the spawn to start.

The hen will start to make the redd with her tail allowing the male to join at a later stage.

Guide Tip: With so many cold spring feed rivers and creeks Michigan has lots of brook trout. Heck, the State fish in Michigan is a Brook Trout want to know where to go? Read -> Where to Fly Fish in Michigan

One More Cast to Brook Trout

So there we have it. It is very possible to fish during the spawn. Maybe not for the specific species spawning, but there are plenty of options to consider as I have mentioned earlier.

As fly fishers, I believe we need to preserve, manage and educate along the way. I say it in this order as many fishers overlook the first two and want to tell others what to do. We need to first make sure the fisheries are sustainable, and if we can teach along the way, then great!

Go grab that 5wt and your streamer box and hit the nearest river.

Tight Lines!

Kyle Knight writer Guide Recommended

Kyle Knight

Fly fishing has been my passion and pursuit for the past 20 years. I am a South African based fly fisherman who loves nothing more than spending a day on the water. Fly fishing is more than catching fish, being in the outdoors with good friends and family is what it is all about.

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