What might be the most critical element in preparing a proper fly fishing trip is stocking the fly box with the right nymph flies.

As the dog days of summer wane, the leaves start to lose their bright green sheen, and it’s only a matter of time before that cool crisp air begins rushing down the mountains. This is nature telling you it’s time to plan your fall fishing outing in beautiful southwest Colorado! 

If you’re like me, planning and anticipating my trips is usually half the fun. I have to decide what to bring, how we’ll get there, and what rivers we will fish among other considerations. What might be the most critical element in preparing a proper fly fishing trip is stocking the fly box with the right nymph flies.

Read the river to find out what bug life lives there. 

Find Out What’s Working

This can be tricky for a number of reasons: what worked well last fall might be slightly different this year. What works on one river might not fly on another, and yes, there are hatches in the fall. However, this shoulder season is notorious for drastic weather shifts: early snow storms and late heat waves that will all affect your fly selection. With that being said, before I offer some suggestions, let me present a few caveats: 

1. Local Intel: I always recommend stopping through the closest fly shop to the fisheries I’ll be visiting and asking the locals what flies have been working recently. There is no substitution for this level of input. If they’re willing to share this information, please pick up a few flies from them to return the favor. 
2. Pay Attention: each week it gets a bit colder, brook and brown trout are thinking about spawning and the hatches continue for midges, mayflies, and even stoneflies. So, it is important to pay attention to what’s going on around you. Part of the joy of fly fishing is piecing together the puzzle of what the fish are eating on that given day as you step onto the river. Pick up some rocks and see what sort of bugs are there. Now see what in your box most closely resembles these critters in shape, color, and often most importantly: size. 
3. Confidence: you will hear it said often in fly fishing circles that at the end of the day, you need to throw the flies that give you the most confidence. How you present the fly is just as important (if not more) than fly selection. If you are feeling confident in your nymph fly selection you’re going to make more accurate casts, achieve drag-free drifts, and cleaner hook sets.

Choosing the right flies means more fish in the net.

With all these variables at play, it is important to keep some key nymphs in the box. These time-tested flies will get you ripping lips on any southwestern Colorado freestone stream this fall:

1. The Copper John (Chartreuse / Red). My first trout in Colorado was caught with a Copper John (thanks to a recommendation from the local fly shop!) and I have always felt this nymph fly was synonymous with fly fishing in the state, no matter the season. This fly is heavy, so it will get down quickly into the feeding lane and the bold colors get the pre-spawn fall trout going. This multi-purpose mayfly nymph imitation is a must for your fly box this fall. 
2. The Double Standard. You won’t see this nymph on many lists, but what you will see is a great debate between two of fly fishing’s oldest nymph patterns: the hare’s ear and the pheasant tail. The Double standard is Tim Flagler’s genius mash-up of the best of two essential nymphs and combines them into one. It’s basically the sleek pheasant tail with the grimy thorax of a hare’s ear.
   The trout won’t have time to figure out which pattern it is before they are chomping down on this bad boy. I have caught fish all over the country – from tailwaters to high mountain streams – using this fly and it is a part of my must-carry lineup. Note: if your fly shop doesn’t have this pattern and you aren’t interested in tying it, I would go with the pheasant tail.
3. The RS2. You will hear about this nymph all over Colorado. This is the fly for the tiny bugs: midges, blue wing olives, tricos, etc. It is an annoyingly effective imitation of all the small bugs found in tailwaters across the state.
   I say annoying because it is so small and so simple. Sometimes we fly fishermen like to overthink things and put on the fanciest new-fangled contraptions we see on Instagram. But what did we talk about earlier? Look under the rocks on the bank and you will probably see tons of early / pupal stage aquatic insects and guess what!? You listened to us and have some tiny RS2s  in your box. Strap one on and thank us later!
4. Some Kind of Worm Pattern. In Colorado, the San Juan worm is a mainstay,  but I’m partial to the chaotic undulation generated by the Squirmy Worm. Yes, I said it. Be careful because this is the red-headed step nymph of fly-fishing. This is because it’s about as close as you can get to bait fishing. People love to hate it but at the end of the day, this isn’t The Louvre, and we are out here to catch fish. Worm patterns will get the job done especially after a recent rain. 
5. Prince Nymph. This classic, regal-looking nymph fly is a super fun stonefly imitation with a million different varieties, pick the one that looks the buggiest to you and keep a couple of sizes handy.

Keep your fly box stuffed with these essentials and you will be well prepared to match what you are seeing on just about any freestone stream in southwestern Colorado this fall.