Fly Tying 1 min read

[Video] How to Tie a WD40 – A Killer Baetis Floating Nymph

Ken Sperry

Posted by Ken Sperry

March 6, 2010

wd40 fly pattern

Tim Flager of Tightline Productions demonstrates how to tie a WD-40, a killer Baetis floating nymph imitation.

WD40 Nymph Recipe

Hook: Dia-Riki 125 (standard emerger hook), sizes 16-24
Thread: Light olive, UTC 70 denier
Tail and wing case: Dyed mallard flank
Thorax: Olive dry-fly dubbing.

Baetis Floating Nymphs

Baetis (a.k.a Blue-Winged Olives) are among the fastest swimming nymphs and can move at speeds rivaling that of some small fish. They can move like a speeding bullet by locking their tails together and forming a paddle of sorts as shown in last week’s video clip from the Bug’s of the Underworld. Unfortunately, our little BWO friends lose this ability when they need it most – when it is time to emerge and make that long trek to the water surface.

Baetis nymphs are a bit like Superman on Kryptonite when it comes time to emerge. Rather than swimming to the surface like a bat-out-of-hell they just float to the surface buoyed by a layer of gas beneath their exoskeleton. Trapped by surface tension they float just below the water surface before popping their wing case and emerging. What fly imitates Baetis nymphs in this vulnerable stage? Why the WD40 of course.

Keys to Tying a WD 40 Fly Pattern

One of the most important aspects of tying the WD-40 is maintaining a slim profile. A tapered thread body helps to keep this super fly slim and looking good from all angles. The WD-40 is often tied in varying shades of gray, olive and brown to match the several dozens of Baetid species that exist.

How to Fish a WD-40 Fly

The WD 40 fly is effective in the surface film, just under the surface, swept up from the deeper zones or on a dead drift mimicking the Baetis nymph behavior just prior to emergence. Early in a hatch you might fish a multi-fly or tandem rig with a larger weighted nymph and later trail a WD 40 off a dry dropper rig.

Regardless of how you fish it, don’t over look the simple looking WD-40, it’s the Clark Kent of baetis floating nymph imitations!


p.s. This video is one in a series on Baetis fly patterns including deep nymphs, floating nymphs, emergers, cripples, duns, wet flies and spinners.