Fly Fishing Experts
Return to all Experts Articles

Fall Baetis For Trout

by Philip Monahan

Have a question you want answered? Email it to us at

Mayfly BaetisFall fish food. Photo Tim Romano

Question: I have always assumed that fall fishing in the Rockies was all about streamers, but I’ve seen guys on Internet boards talking about fall Baetis hatches. I thought Baetis was a spring bug. Is it the same thing?

Joe F., Los Angeles, CA

Answer: Well, yes and no. The Baetis species that hatch in the fall look just like the blue-winged olives of spring, but they’re usually smaller. Whereas you can cast a size 14 or 16 dry-fly pattern in spring, you might have to drop down to an 18 or even go as small as size 22 (especially on spring creeks or flat pools) in the fall. Depending on weather and water conditions, though, you can find occasional good dry-fly action through mid-November.

As with the spring BWOs, fall Baetis love crappy weather, so if the forecast calls for overcast skies and light rain—or even a few flurries—bundle up and get out on the water. One of the good features of these autumn hatches, however, is that they mostly occur at midday, from about 11 a.m. to late afternoon. That means you don’t have to drag yourself out of bed early to freeze your butt off.

If you do get to the river before the hatch begins, focus on subsurface presentations, using a tandem-nymph rig of standard Baetis fare: Pheasant Tails, Hare’s Ears, and the like. The water is getting colder and the fish will be slightly less active, so focus on side channels and slow-water sections. Make sure you allow the flies to swing at the end of the drift to imitate emerging mayflies, or try a Leisenring lift to target your presentation to specific lies.

When the bugs do start popping on the surface, switch over to a two-fly setup with a Sparkle Dun or Parachute Adams on top with and a BWO emerger or unweighted Pheasant Tail as a dropper. One of the differences between spring and fall Baetis fishing is that the autumn fish are generally less gullible, having endured through an entire season of angling pressure. You may need to go down to 6X and your presentations may have to be spot-on for consistent success.

MidCurrent Fly Fishing
Phil Monahan is a former Alaskan guide and was the long-time editor of American Angler magazine. He's now a columnist for MidCurrent and writes and edits the fly-fishing blog at You can email your fly fishing questions to us at
This article is filed under Experts with sub-topics , , . Bookmark the permalink.
  • lilrhodes

    Great information, and I really like the suggestion – “or to add an unweighted pheasant tail nymph as a dropper.” I will use this!!  I recently tied up a new batch of unweighted nymphs, but get so excited on the water that I automatically go to the bead heads without thinking.  Thanks!!  This will reemphasize, to me, to use the more natural unweighted version an possibly fool more of those wise end of season trout. I fish in Italy, and there is lots pressure on the water with wild trout. . . and the same size/type BWOs are on the water here, just like in the USA. The 6x tippet is a necessity (no joke, either), along with a 12 to 15 foot leader combination to avoid any drag on the calm water sections with drys or spinners, and the largest BWO pattern is size 18 down to 22.  I’ve designed my own delicate realistic presentations, always trying to improve on them.  But, I love these BWO hatches and matching wits with these selective trout.  I’ll use some wet flies too, size 14 to16 usually (also tied delicately), with consistent success before the hatch gets going – usually right before the hatch. With the tandem nymph rig, I use a leader the size of my rod i.e. 9 ft rod 9 ft leader. It is much easier to cast the flies with control this way with an open rounded cast or water load combination, and I fish the European/Czech Republic style high sticking. Or, I’ll combine it with a wet fly on the top part of the rig with a nymph below using a hybrid Czech/wet type drift – always having contact with the line and rod tip lowering with the drift. . . at the middle to end of the drift low to the water or even sometimes rod tip in the water if necessary to get the correct drift and level in the water. I, also, saw this technique used this year at the World Fly Fishing Competition, here in Italy, with success.

  • Jcrosby Jerecrosby

    What made all the difference in the world to the success of my BWO fishing in the Fall, last year, was to capture an adult, and check the body color.  I got skunked until I did that, and then saw that the body was a chartreuse  green.  The body was as bright as a light bulb chartreuse, and when I changed, and fished a small dry using that body color it was instant success.  They were much smaller than the Spring BWO’s and I use the short shanked caddis pupa hooks that have a bigger gape, and you can come close to matching the size, and have more fish holding power, and more fish landed.

  • DP

    It is also important to point out that baetis have multiple species and many are multi-brooded, which means they can lay eggs and have another hatch in the same season instead of living an entire year as a nymph. It is the multi-brooded trait that causes them to diminish in size over a season and even though a given hatch period over time.

  • Carpino72

    Very informative response would you recommend the same tactics for fishing in the UK in early Feb-march

  • oldguardvet

    Don’t forget the diving/crawling egg layer’s too! Simple olive dressings with a clear Antron wing fished wet can really get attention. Trout like the flash of the wing. It’s the trigger.

  • Brian Larson

    Actaully I ahve found taht fall olives don’t really mind sun. They seem to keep on coming up regardless.