Best Baetis Nymphs

Blue Winged Olive mayflies are an abundant insect found in most western trout streams. They are also referred to as Baetis or BWO’s. During the shoulder seasons in the spring and fall, Baetis hatches can be prolific, and we need good fly patterns to imitate them. Although fishing Baetis dry flies can be a blast, nymphs will usually get you more bites.

This article will cover my favorite Baetis nymphs for fishing Colorado. The patterns below are tried and true, and they will work anywhere there’s Baetis present. If you plan on fishing for trout during the spring and fall months, I highly recommend picking up a few of these flies.


Developed by Rim Chung, this fly has been famous for a long time. It works year round as a mayfly imitation, and it can be fished deep or shallow. Popular Rs2 colors are olive, black and grey (dun). There are many variations of this fly – sparkle wings, CDC wings, etc. I like to fish sparkle wing Rs2’s in dirtier water, but the CDC wing works better in clear water.

The Rs2 has been working for decades, and it remains popular year after year. I actually have a whole fly box dedicated to Rs2’s, and I recommend all fly anglers carry some.

When using Rs2’s for a Baetis hatch, I usually use a grey (dun) version in sizes #20-#22.

Pheasant Tail Nymph

This is a very classic fly, which pretty much works all the time. There are dozens of Pheasant Tail variations – beadheads, soft hackles, and unweighted versions. For imitating Baetis, I like to fish slimmer pheasant tails with no bead. These look a lot more like a natural Baetis, and they’re one of the best imitations around. I find slim pheasant tails really important for imitating Baetis, and some brands like Umpqua have slim versions available.

Similar to most Baetis flies, I will fish Pheasant Tails in sizes #18-#22.

JuJu Baetis Nymph

This is one of my favorite Baetis imitations out there. Designed by Charlie Craven, the JuJu Baetis will fool trout any time there are Baetis around. It comes in a multitude of colors, and they all work well. It is also available in a tungsten version as well as an unweighted version.

I will fish this fly in sizes #18-#22, going smaller as needed when the trout are picky. It can be sunk deep, but you can also fish it unweighted – close to the surface. Fishing it in the surface film can be really effective when there’s a Baetis hatch happening.

The fluoro fibre legs really shine in the water, which gets the trouts attention. I have yet to have a bad day with the JuJu Baetis.

I recommend every trout angler has at least a few JuJu’s in their fly box.

Radiation Baetis Nymph

This is a Shea Gunkel pattern that quickly gained popularity in Colorado. It is now famous all over the US, as fly anglers realized just how effective it is.

The Radiation Baetis is a beautiful, ultra realistic Baetis imitation that works in all trout rivers. The fluoro fibre legs really add life to this fly, similar to a JuJu Baetis.

One key thing about this fly is the hot spot collar – it attracts trout and gets them to really see the fly. The thorax of the fly is also a hot spot, which is unique to the Radiation Baetis. I find the orange hot spot works well most of the time.

I usually fish the Radiation Baetis in a size #18 or #20.

Hide-A-Bead Baetis Nymph

This fly is from Solitude Fly Co. I love the Hide-A-Bead Baetis because it provides tungsten weight, while hiding the actual bead. The bead is hidden under the thorax of the fly, which is a truly great design. On top of this, the Hide-A-Bead is very proportionate and looks like a real Baetis nymph.

I usually fish this fly in a size #20, which seems to cover most Baetis hatches. The Hide-A-Bead works well when you need to fish deeper holes. It also works well under a dry fly for a “dry-dropper” setup.

Mayhem BWO Nymph

The Mayhem series of flies are super effective. There are Mayhem midges, Mayhem BWO’s, and Mayhem PMD’s. They are quite a simple fly, but extremely productive in most trout streams.

The foldover casing looks very realistic, and will fool trout during all Baetis hatches. As with most of these nymphs above, the Mayhem can be sunk or fished in the surface film. I find the Mayhem to be really effective when the trout get picky – especially on tailwaters. If you drift this fly in front of them, they will be fooled.

The Mayhem BWO is from Solitude Fly Co, and is available in most western fly shops. I prefer them in a size #20 most of the time.


Every fly angler has their favorite flies, so this article is obviously opinion based. However, after fly fishing in Colorado for years, I truly trust these patterns whenever there’s Baetis hatching. After cycling through many unproductive patterns, we generally stick to the ones that fool the most trout.

If you are just starting to build out a Baetis fly box, definitely consider the flies listed above. They have been proven effective even on the toughest days. Especially when fishing tailwaters like Cheesman Canyon or the Fryingpan.

Baetis are one of the most important insects for trout, so it’s important that fly anglers come prepared.