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Home->Articles->Phils Articles->Archives->Hitchhikers Guide to Chironomids Part 1   
Phils Articles
Hitchhikers Guide to Chironomids Part 1


Trout of all sizes love chironomids.
The wind was up and the weather was still in the final convulsions of a low-pressure system.  Understandably, fishing was slow.  Moving from the protected shallows into deeper water the subtle swirl of a feeding fish caught my attention.  Looking closer I began to notice other trout moving at the surface.  The wind moving across the surface created wind lanes, foam lines and slicks known as Langmuir Spirals.  Trout were moving upstream in these slicks and picking off the large Chironomid pupa that were now completing the final stages of their ascent in ever increasing numbers.  It was time to drop anchors and feed some fish.


I was now in 15 feet of water, I checked my leader and added a new section of tippet increasing its overall length to about 19 feet.  Stripping out enough fly line for a long wind assisted toss I punched a quartering cast out into the small swells sat down and patiently waited for the size 10 Christmas Tree pupa pattern to sink.   In 15 feet of water it would take 3 full minutes for the fly to cascade into the depths.  As time passed an increasing number of obese adult chironomids swept by, abdomens hanging down in a vain attempt to maintain an element of grace and style amidst the frequent gusts of wind.  During the swing of my third cast the fly line darted through my fingers under the pressure of a confidant grab, so much for the so-called subtle “chironomid” take.  Within seconds I was into my backing and at the mercy of a 4-pound fish cart wheeling amongst the chop, not the least impressed with this whole chironomid thing.


After a quick, caring use of my throat pump I cradled the rainbow boat side waiting for her to gather the strength to swim away and perhaps allow another angler a similar experience.  She swam confidently down into the depths forever etched in my memory.  Snapping out of my euphoria I remembered the throat pump and squirted the contents into a vile.  Inside the vile 8 to 10 large olive brown pupa wiggled and shook still intent upon hatching.  After four days of inclement weather and wind the tide was beginning to turn.  Fish were feeding and the chironomids had finally come out to play.


Life Cycle


Chironomids are arguably the most important food source for stillwater trout and char throughout the open water season.  As with all food sources success for the fly fisher depends upon an intimate knowledge of their life cycle.  Over the course of the season trout see enough chironomids that they react in a conditioned almost Pavlovian response regardless if there is a hatch or not.


Chironomids are the number one food source during the open water season.
Chironomids belong to the insect order Diptera and are characterized by a four-stage life cycle or complete metamorphosis.  The female lays demursal eggs during the early morning or evening hours when the waters surface tends to be calm and the risk of avian predation from birds and other insects is low.  The eggs drift down to the bottom were they soon hatch into the larval stage.  Many anglers know the larval stage by their common name, bloodworms.  So named due to the fact that many species contain hemoglobin that gives them a distinct scarlet or maroon coloration.  Hemoglobin allows the larva to live in oxygen poor water and as such bloodworms can be found to depths of over 100 feet.  Other color considerations include olive, green and a unique candy cane combination of red and green.  Most species of chironomid larva and there are over 2500 chironomid species in western North America alone, construct tubular homes in the mud water interface along the bottom.  Muddy-bottomed lakes such as Tunkwa and Leighton are favored habitat and are home to epidemic populations of chironomids, many reaching huge proportions of over an inch in length.  Other species are free living while some spend the first stages of their larval cycle as free-living larva settling down to a benthic existence as they mature.  Within the safety of their homes the larva pulse their worm like bodies to draw detritus and other food sources into their tube.  Feeble swimmers the larvae move through the water with a lashing head to tail motion reminiscent of a severed worm.  Despite this handicap larva often leave the sanctuary of their homes to forage and migrate.  Spring and fall are two such times for these migrations and larval patterns should be primary considerations.  During low light hours chironomid larva often venture out for a feed making a bloodworm pattern a favored lead off hitter.  Plying the waters after a good windstorm with larval imitations is another wise strategy as many larvae are swept from their homes by the swells and aggressive wave action.


Depending upon the species chironomids can spend up to 1 year in the larval stage.  The larva seals itself within its tube or constructs a temporary dorm to transform into the pupa.  During this transformation the larva develops wing pads and a distinct thorax. When the time is right the now transformed pupa cuts its way free and prepares for its trek to the surface to emerge.  Contrary to popular belief the pupa does not rocket skyward but rather stages and hovers near the bottom.  From personal aquarium study I have seen pupa take up to 4 days to elevate to the surface and hatch.  This explains why fishing pupal patterns can be deadly while their appears to be little evidence of an impending hatch at the surface as below trout feed upon this suspended smorgasbord.  During this staging process the pupa absorbs air and gases under its pupal skin.  Starting off as a dull almost gun metal sheen these air and gases turn the pupa to almost silver as the emergence process nears the end.  These trapped air and gases often obscure the pupa’s natural coloration.  Still there is another caveat the volume of trapped air and gases varies also and during the pupal ascent a pupa’s color can change and vary in intensity.  As if things weren’t complicated enough.  Common pupa colors include black, maroon, olive, brown and various shades of green.  The well-stocked fly box should include a cross section of these colors plus silver bodied patterns in sizes 18 through 8.  For the fly tyer there are a host of materials to choose from including Frostbite, Angel Hair, Super Floss, Stretch Flex, Flashabou and Krystal Flash.  The permutations are endless.  In addition to body color chironomid pupa are adorned with prominent white anterior gills and some species also posses smaller less visible posterior gills.  This feature should be a characteristic of any descent pattern.  But perhaps the most important trait from an imitation perspective is the overall slender profile of the pupa.  Overweight bulky patterns should not be considered. 


When the pupa is ready it begins its slow methodical ascent by elevating its way towards the surface.  The pupa also throws the odd undulation in for added thrust and as it nears the surface this practice increases.  At the surface the pupa hangs in a comma posture for a period of time, often temperature and humidity dependant, then lays horizontal.  A split forms along the thorax and the mosquito like adult crawls out, dries its wings and flies away towards shore.  These fledgling adults are easy pickings for Swallows, Nighthawks and other predatory birds.  On most interior lakes this emergence process takes seconds and trout have little or no time to feed upon them.  But there are exceptions.


The adults now begin to form huge mating swarms along and near the shore.  From a distance these swarms resemble dust or sand storms.  Walking amongst one feels like being pelted by tiny particles.  The females fly into these swarms were mating takes place.  These gravid females wait until the off hours of morning or evening to lay their eggs and complete the lifecycle.  At certain times the egg laying flights sound like distant race tracks as the females return to the waters surface.  I can recall one occasion on Leighton Lake when the there were so many adult chironomids on and over the water it was hard to breathe without eating three or four.  The small cooler in my boat was coated with adult chironomids.  Fish gorged themselves silly in the fading light but one had to practically fire the pattern down the trout’s gullet to hook up, as there was no need for a trout to waver in order to feed.  The trout would adopt a feeding rhythm and nothing would persuade them to change.  Once the mating and egg laying rituals are complete the adults soon die, another generation of chironomids laid and ready to take their place.




Floating lines coupled with strike indicators have become the prefered presentation technique.
Although standard stillwater fly-fishing gear in the five to seven weight range will suffice for most chironomid scenarios there are some key points to consider.  Try to avoid stiff fast action rods.  Moderate to medium action rods from 9 to 10 feet in length allow for greater sensitivity in detecting strikes, loop control to afford wider casting loops when casting fifteen foot plus leaders and forgiveness on the hook set avoiding break offs. 



The past five years has seen an explosion in the types and options of fly lines available to the fly fisher.  To some it is near the point of intimidation and the final buying decision as difficult is as it has ever been.  The floating line is the primary weapon in the chironomid fly fishers arsenal.  Popular favorites include Scientific Anglers nymph taper, ideal for turning over weighted flies and indicators and Rio’s new Rio Grande.  Airflo has introduced a new Indicator Tip line that features a foot long fluorescent orange floating tip married to an olive running line.  This combination provides a noticeable reference point for the angler to detect strikes even at a distance under a mild chop. 


Other lines that should eventually work their way into the kit bag include a full sinking line of at least a type II density.  As we will explore in part two of this guide, sinking lines are a valuable alternative to floating lines in certain situations.  No matter who the manufacturer try to purchase a density compensated sinking line.  Designers of these lines have adjusted the sinking properties of their lines so the tip section sinks first aiding strike detection measurably.  The clear intermediate and traditional intermediate lines are another versatile consideration especially in windy conditions.  Depending upon the brand there are different sink rates from Airflo’s slow glass at paltry .8 inches per second to Cortland’s Clear Camo at 1.5 inches per second.  It pays to read the box.  Although not a personal fan of sink tips for lakes the new clear or midge tip fly lines are a worthwhile investment.  Rio’s Midge Tip and the Teeny Versi-Tip are 2 options for the fly fisher.  For those not wishing to invest in such lines try using Airflo’s Poly Leader system.  Available in 5 and 10 foot lengths these leaders run from floating sections down to a bottom dredging super fast sink rate of 6.1 inches per second.  Their loop-to-loop connections allow the angler to adapt their floating lines to manage a variety of presentation challenges, from wind to increased depth.


Leader and tippet options are not nearly as convoluted as lines but still there are choices.  For the majority of presentations use a standard tapered leader from 9 to 15 feet in length.  Tapered leaders allow for proper turnover and presentation.  In the case of a floating line set up simply add tippet to the leader to cover the depth required, typically 25 percent more than the water is deep.  Water clarity is a primary consideration too.  Take White Lake near Salmon Arm for instance.  This challenging body of water often requires anglers to adopt a fine and far off approach.  Short thick leaders and tippet typically pitch a shut out.  When using indicators a degree of economy enters the equation.  Since the fly and the indicator tend to flop the leader over a tapered leader is not required.  Most seasoned indicator fly fishers use straight running line from 8 to 4 pound breaking strain.  This skinny set up cuts through the water fast helping drag the fly down to its working depth.  Fluorocarbon has become increasingly popular as well despite its relative cost to traditional monofilament.  It is often the difference in clear conditions and finishing off the leader with a final 2 to 4 feet of fluorocarbon tippet is always a sound tactic.  Remember to use a triple surgeon’s knot to avoid breakage.




Once upon the water the angler needs to establish their working platform.  This translates into fishing from a firmly anchored boat float tube or pontoon boat.  Chironomids are not suitable for trolling or drifting around aimless and out of control.  For boat anglers double anchoring is the norm while float tube and pontoon boats should single anchor for hopefully obvious reasons.  Where to anchor is dependent upon individual angler observation.  This begins on shore by scouting the shallows for signs of a hatch from swarming adults to shucks washed upon the shore.  Spider webs are another collection point, giving clues to both color and size of the hatch.  Once on the water look for shucks and emerging adults on the surface, birds such as Swallows actively working, and of course chart the success of other anglers from a safe and courteous distance.  Keep in mind that most hatches can be specific and localized and only one area of the lake may support active feeding fish. 


Hopefully we are now conversant in the life cycle of chironomids and how their size shape color and behavior should relate to both the fly box and the beginnings of on the water presentation.  What considerations there are in regards to rods lines and leaders.  Once on the water we have an idea of how we should set up the boat float tube or pontoon boat and where we should go based upon our observation skills.  In the next segment the focus that all important element presentation.  Pattern choices, what fly line to use and why, the pros and con’s of fishing both with and without indicators and some of the other options afforded through intermediate and slow sinking lines.

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