Dry Fly Fishing On Reservoirs – An Underated Approach

10:51 am

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This article discusses dry fly fishing on reservoirs, I’ve had to make some generalisations, but the principles are likely to apply widely. For the purpose of the article, the term “dry fly” also refers to flies classed as emergers.

As a full-time fly fishing guide and coach, I watch lots of anglers. Not just those I teach, but I observe many anglers tackling up and fly fishing from bank and boat.  Many anglers fish lures or wets on reservoirs regardless of conditions or fish behavior, if you want to catch higher than the rod average – this is a big mistake!

Lures work well on reservoirs. There is no doubt about that. Freshly stocked rainbow trout are aggressive and greedy and will take a fly stripped past them.

There are however many times when they will not. Once a fish is accustomed to the water, and natural food is available, fish will be more likely to lose their aggressive nature. Have you ever been on the reservoir and seen lots of gentle rises (probably at small midges) and tried stripping a lure through them? I’ve witnessed it many times, and the answer is nearly always a blank.

In May, as the weather starts to warm and food becomes available to the fish, using natural patterns including dries will be a very productive approach.

Many anglers I observe do not even consider their fly choice, the weather conditions or even what they see in front of them before commencing fishing.

I was coaching a group of 4 total novices at a fishery in April, and there was a large hatch of hawthorn fly in the surrounding fields, many of which found their way on to the water. The fish were having a field day, and I quickly tied on hawthorn imitations to my group’s leaders which accounted for multiple fish over the next few minutes. I remember two other anglers both pulling lures who couldn’t understand why they were not catching when my complete beginners were doing so well!

So, if you don’t already do so, try to consider using dries as an option if conditions suit, it’s great fun and will outfish lures significantly on the right day.


Fear Of  Using Dries

There are two main reasons why people are put off using dry flies in a reservoir. The first is the fear of being passive. When you are stripping lures or pulling wet flies you feel like you are doing something, you feel like you are working to earn a fish. Dry fly fishing is often passive. If you are not a patient person, it’s difficult to let a fly sit in the ripple and watch it! The way around this is to get some rises and catch a few fish using this method to build your confidence.

The second most common fear is the fact that small dries look so tiny in such an expanse of water! How will the trout find such a small fly? Well, for those of you that take stocked rainbows for the table, next time you gut your fish, take a moment to examine the stomach contents. You will find that many of the insects are indeed small. Next time you are aware of lots of fish sipping on midges, take a minute to examine the size of the specimens in the air – they are tiny! Trout have remarkable eyesight; if they have their eyes up, they will see your fly.

Times of year

Trout are opportunists and provided conditions are favorable, your quarry can rise to dries at any time of year. There are however two times of year when surface fishing will be especially productive.


Once the water temperature rises, Trout will become far more active in searching out their food. Luckily for the fly angler, this time of year usually coincides with the first significant fly hatches of the year. Hawthorn flies from surrounding land will be blown on to the water. Fresh green leaves on the trees become home for beetles and other terrestrial food sources which the winds converts to waterborne food sources for cruising trout. 


The backend of the year is particularly productive for dry fly fishing on reservoirs. A superb fly at this time of year is the Daddy Long Legs; any decent pattern will work. Many times I have been coaching with clients on the bank where they have caught multiple fish on Daddies at close range while other anglers blank struggle pulling lures or wets. Late September and October are two excellent months for dry fly fishing. Surface activity will generally drop off with the arrival of the first frosts or chilly easterly winds.


Poor conditions

Bright cloudless days,
High (20c+) or low water temperature (below 5c),
Cold winds,
High winds,
Very heavy rain,
Millpond like flat water 

Ideal conditions

Reasonable  water temperature – 15c is widely used as an optimum
Dull overcast day,
The gentle ripple from a light westerly breeze  

Evening and Morning rise

On my local reservoir the trout will rise from the first signs of dawn until the sun hits the water, then, like clockwork, they will disappear (on a bright day) until the sun recedes over the hills. If you can fish your local water during these times, you will certainly improve your catch rate (particularly) during the warmer months.

During the evening you may also have fish rising to spinners (mature upwing flies) and caddis flies which can provide excellent fishing on dries.

Insect Life & Flies

Many reservoirs are quite barren. Often the water is fairly acidic which creates unfavorable conditions to support the volumes of the aquatic life trout require. Lots of the surface food that trout feed on in reservoirs will either be terrestrial (blown on from surrounding land) or midges (prolific is all reservoirs) there will also be caddis, mayflies and other types of aquatic flies but these may be localised. Midges and terrestrials are a definite, no matter where you are fishing. Therefore, it makes sense to base your dry fly box around some reliable food sources. I have included below an excellent selection of dries that will work well on many reservoirs.


I think the muddler deserves a special mention. The muddler fishing fly was developed in Canada to catch river-dwelling brook trout. It is now widely used in still water fly fishing as a surface fly. Muddlers probably resemble small fry struggling in the surface or even a large caddis skittering along, or they appeal the aggressive instinct of feeding trout. They are excellent surface flies and are very useful in spring when the fish are chasing their food. You can strip them through the ripple to create a wake which will often induce a take given the right conditions.



Fishing dries is essentially very simple. Often you will be fishing a single fly, and you will be using a floating line. The two most common mistakes people make when fishing dries are:

Casting too much – this comes from the fear of passive fishing, the need to be doing something. Present your dry and leave it for as long as possible before recasting. Much of the time you will be catching fish that are cruising the margins searching out food, the more time you give your fly in the water the more likely you will intercept a fish.

Fishing out of range – unlike when you fish with moving wets, there is no movement in the fly to help set the hook. The setting of the hook must be achieved with the strike. If you are casting too far, then much of your strike will be taken up by lifting line off the water, and you are not likely to set the hook properly. From my experience, you are just as likely (provided there is a reasonable depth) to catch fish at a few rod lengths in front of you as you are double hauling 80 feet of line. Fish the water in front of you and forget about long distance casting.

Stay In Control

It’s essential that you stay in touch with your fly when dry fly fishing. When a fly line sits on the water in will naturally kink and coil, couple this with any current and wind and you will get slack in your line quickly. It’s imperative that you retrieve this slack to make sure that striking sets the hook.

To Twitch Or Not

Sometime fish will respond very well to a fly twitch along the surface. In nature, emerging caddis flies, mayflies and crane flies (amongst others) often struggle and skitter along the surface film. When imitating these types of fly, it’s worthwhile adding a little movement to the fly to see if you can induce a rise.


Seeing rises

Time spent in reconnaissance is seldom wasted. On big waters, it’s certainly worth having a quick scan round to see if any area of the water is producing rises. There may be localised hatches at a particular time of year. We have certain bays on our local reservoir that produce a good hatch of Mayfly while others don’t. At the very least it’s worth asking the fishery staff, especially if you are unfamiliar with the water

Using The Wind

If the wind has been set in its direction for a number of days, food will be blown accordingly. It can be a good idea to start fishing facing into the prevailing wind to pick off fish who have latched on to the windblown food.

Cast & Move Or Stay Still?

There are two schools of thought.

  1. Keep moving and find fish
  2.  Stay where you are and ambush fish swimming past you

There is no right answer here!  If you are dry fly fishing, generally speaking, you are fishing on days when fish are active so either option can work. Trust your instinct and move or stay if you feel like it. There will come a time when, if you haven’t even seen a rise you will benefit from moving to try different spots.


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