Fall Baetis For Trout

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Fall 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.