Hatches and Fly Patterns for Connecticut’s NW Corner and the Hudson Valley


“What fly should I use?” is a question that all fly anglers will ask time and time again. The following is a basic seasonal guide for our area. Much of this information applies generally to neighboring watersheds from the Catskills to the Connecticut River. Different streams have some variation in orders and species of insects, but I’ll attempt to provide all angling levels a seasonal emergence strategy, and fly selection guide. 

Water conditions can vary from season to season. The strategy section gives anglers some options and approaches to consider.

The quantity and variations of fly patterns has continued to change and multiply. The fly names used here to identify patterns are the common fly shop/fly fishing catalog names for imitations of common aquatic and terrestrial food sources. Emergers represent insects that are transitioning from underwater nymph and pupa stages to that of winged adult. Spinners are sexually mature mayflies that are about to mate or have mated and are laying eggs on the water to begin the life cycle once again. CDC refers to feathers taken from the bottom section of a Mallard Duck -commonly known as the butt section of a duck. It was once thought that these ducks have a gland in this area that produces an oil, that ducks spread over their bodies to make their feathers water resistant. This theory was disproved when the feathers were later found to have spines, and the spines contain little barbs which contain trapped air, thus causing the feathers resistance to sinking. CDC is short for “Cul de Canard“, which is French for “Duck Bottom”.

Most fly shops carry the flies mentioned in this guide. If you don’t see it, ask for it. Many of the flies in the photos were taken off the FlyShack website, others from the Big Y Fly Co website, and still others were taken by me when I wasn’t able to find anything online. Your comments will appear once they’ve been verified.

State Regulations

New York’s Hudson Valley’s cold-water streams  have a season that begins in April – check their regulation annuals for details. Connecticut TMA sections in streams where catch and release is the key, have no season and fishing is open all year – again, check the Connecticut regulations for details. Annual Connecticut regulation are available in digital form on this website.

Winter Season: December – March

Water conditions:

Water temperatures usually begin somewhere in the 30ths or 40’s and fall as the season progresses. Use the USCGS gauges (found under the Resource Tab on this website) to determine water and air temperatures. Use the NOAA.gov website for daily weather forecasts. Falling and melting snow will decrease water temperatures. Nymphs and streamers produce most of the fish, however there are a few midge hatches on days with low wind conditions.

Key factor – Water temperature

If water temperatures reach 50 degrees or above, insect and fish activity increases.


Blue Winged Olives, Blue Quills, Blue Poison Tung, Winter and Black Caddis, Black and Little Brown Stonefly.

Blue Winged Olive Dry, Nymph, Wet & CDC patterns
Blue Quill Dry, Emerger, Nymph and Wet patterns
Blue, Deep Blue and Original Poison Tungsten winter nymphs
Blue, Deep Blue and Original Poison Tungsten winter nymph patterns
Biot Wing, Black Slow Water, Elk Hair, and Little Black Caddis
Biot Wing, Black Slow Water, Elk Hair, and Little Black Caddis patterns
Winter Caddis tied on jig hook for quick decent, larvae nymph, nymph and Winter Caddis Adult Patterns
Two Images of Little Brown Stonefly patterns

Strategy: Fish streamers and nymphs low and slow. Fish from Sub-surface down to the bottom. Remove ice from surface flies with the warmth of your fingers.

Cold Weather Tip

Spray PAM or other cooking oil on the guides of your fly rod to decrease ice from forming and blocking the guides. Wear chemically activated foot warmers between your socks and the bottom of your stocking-foot waders, keep the warmers inside the waders. Dress for bitter cold even if the day seems warm -periods of cloud cover where the sun isn’t shining can come on suddenly and drive temperatures down quickly.

Spring Season -April

Water Conditions:

Water temperatures usually start out in the 40’s and rise as the month progresses. Melting snow and spring rains will increase flows and drop water temperatures. During  a dry winter and spring, low/clear water conditions will prevail. If stream flows are high and off-color or stained, and water temperatures are still in the high 30’s and low 40’s, most action will continue below the surface with nymphs and streamers. If temperatures are higher (40’s and 50’s) fish will be more active and surface feeding may be taking place. Sub-surface (Nymph and/or wet fly) activity should be high.

Key factor – Water temperature.

Water temperature is the critical factor. When water temperatures rise to 50 degrees or above, insect and fish activity increases. During this time, streamers and nymphs are the best bet.


Mayflies: Blue Winged Olives (BWO). Hendricksons may begin to appear as water temperatures and sunlight increase. Quill Gordons may also appear.

Blue Winged Olive Dry, Nymph, Wet and CDC patterns
Hendrickson Dark, CDC Comparadun, Nymph, actual Live Fly, Light, and Parachute Dark patterns
Quill Gordon Dry, Dry, Emerger, Wet, Dry and Nymph patterns

Caddis & Stonefiles: Black Caddis and Early Brown and Black Stoneflies continue. A variety of Caddis can provide excellent surface activity. Midges are an important foodsource and are often overlooked by anglers. Baitfish minnows are a major foodsource in this area of the country. When it comes to Stoneflies, everyone has their favorite. The Yellow Sally family of stoneflies is huge, (first two lines of images). Every year it seems another tier has created a Yellow Sally to act differently, float on top, stay in the film, stay a few inches below the surface, ridge just below the surface….

Stonefly Images:

High Rider Low Rider Low Rider Nymph Huge Appetite
Bottom Bouncher Winged Sally High Rider Nymph Nymph on Scud Hook
High & Dry Slow Water Low Rider Live Larvae Nymph Low Rider

What is a Hendrickson?

The Hendrickson is a mayfly belonging to a family of mayflies that provides many important fishable hatches throughout the season. This mayfly has slate gray sailboat wings with either a yellow/gray or pinkish gray body for the larger female or a reddish brown body for the smaller male. Males also have more pronounced and larger eyes. Hook size related to the insect varies from a #12 to a #14. Body color can vary slightly from stream to stream.

Hendrickson Dark, CDC Comparadun, Nymph, actual Live Fly, Light, and Parachute Dark patterns

The name “Hendrickson” originates from a trucking business owner, A. E. Hendrickson; who fished the Catskills region with Roy Steenrod, a master fly tier, in the early 20th century. In the spring of 1918, Steenrod tied up a few flies to imitate the mayfly that was hatching on the Beaverkill River. This un-named fly was deadly, and he and Hendrickson had a number of great fishing days on the water. Later, Steenrod decided to call the fly the Hendrickson after his friend and fishing companion. The common names of flies often have little to do with science. This fact causes great confusion to new fly anglers. Once you become familiar with the vocabulary of insects and flies, it is much easier to understand what different flies are made to imitate. Besides, you don’t need to know the name of a fly to catch fish with it.

Strategy and Flies:

The Hendrickson is the big story as far as hatches at this time of year. The Hendrickson mayfly begins to emerge the 2nd or 3rd week of April. This is often the first really fishable hatch in the region that can provide good dry fly activity. The hatch cycle is initially sparse and then becomes increasingly abundant as the days go by. During a colder spring, the hatch may be delayed into May. Fish the Hendrickson during the pleasant part of the day (afternoons, 1:00pm or earlier on warmer days). Look for Hendrickson spinners returning to mate and lay eggs in the evening once the hatch has been on a few days. Try a brown floating nymph hook #14 early on a Hendrickson Hatch. Streamers may produce larger fish.

Fly Patterns: Nymphs and Streamers

Pheasant Tails or dark brown Hare’s Ear Nymph – #12-#14

Pheasant Tail Nymph, Soft Hackle Pheasant Tail Nymph, Variation Tied on Jig Hook
Standard Hare’s Ear Nymph and Gold Ribbed Hare’s Ear Nymph

Dry Flies:

Rusty Brown Spinner (#12-#14), Hendrickson Emergers (#12-#14), Grifith’s Gnat (#18-#22) which imitates midges and other small aquatic insects.

Rusty Brown Spinner Realistic Looking Wings, High-Visibility


Henryville Special, Elkhair Caddis, Woodchuck Caddis (#14-#18)

Elkhair Caddis, Henryville Special, Woodchuck Caddis.

The importance of Caddis Flies:

Caddis flies are almost always present in our part of New England and upstate NY. This aquatic insect is profuse and differs greatly in size, color and behavior on the water. Caddis flies undergo a complete metamorphosis from larvae to pupae to adult. The actual insects appear moth-like and their wings are held in a tent-shape fashion over their body. Larvae can live in cases fashioned in sticks, stones, and other plant material. There are also species that spin nets for capturing food or others that live free-ranging without cases. Oftentimes, when you check a trout’s stomach you’ll see a healthy amount of small twigs and stones. This is likely a hint that the trout has been eating a steady diet of Caddis flies. I actually have a recipe for tying the casing made from stones and little twigs.

Special Insert – Zebra Caddis/Alder Fly

Alder Fly – Actual, two examples Dry, live Larvae, two examples wet

During the months of July and August, on the Housatonic, Naugatuck, and Farmington rivers in Connecticut, normally during the evening, a large hatch takes place – the Zebra Caddis, or commonly called the Alder Fly. This is an important event, because after it, during the summer months the size of the fly you’ll offer will get down into the smaller offerings.

Spring Season: Early May

Water Conditions:

Water and air temperatures continue to be moderate. High water as a result of spring rains can be a factor. Fish and insect activity are in full swing.

Key Factors: Warmer or cooler weather could speed up or delay insect emergence. Streamside vegetation increases. Hatches begin on lower warmer sections of streams and move upstream.


Hendrickson emergers and Caddis emergers during the day. Spinners in late afternoon or evening. After the Hendrickson hatches have completed their run, try March Brown and Gray Fox. In shallow riffles, try Ausable Wulff.

Continued use of BWO, Blue Quill, Black caddis. Caddis hatches are heavy on the Housatonic, Blackberry, Shepaug, Naugatuck and tributaries in May. Watch the Housatonic River for a huge Hendrickson hatch in mid May. Also, fish the Adams, during evening spinner activity.

Ausable Wulff dry Gray Fox Hendrickson CDC Emerger March Brown CDC Emerger

Spring Season : Mid May to mid June

Water conditions:

Water temperatures drop into the 50’s on cooler night and rise into the mid 60’s  during the day. The character of the water begins to impact hatches and where the trout position themselves. High water (watch out waders) from rainstorms is possible and make wading difficult.

Key factors: Water Temperature

Water temperatures are usually at optimal ranges for trout unless an early heat wave prematurely heats up the streams. Streamside vegetation becomes a factor for anglers and fish. Trout will be feeding on a regular basis. March Browns and Grey Fox hatches begin around the same time as lilacs bloom. Sulphurs’ dominate in the Mid-Hudson while crane-flies, Usuals’, Caddis and soft-hackle wet flies dominate in the Housatonic watershed. In early June the Housatonic has a very short Green Drake hatch. On the Ten-Mile, Housatonic, Blackberry and Naugatuck/rivers try March Brown, Gray Fox, Ausable Wulff, Sulphurs, Light Cahill, Yellow or Golden Drake, BWO, Slate Drake, Lead Winged Coachman, Copper John, crane flies and midges. Also, in mid-June, terrestrials become food on windy days. Try ants, beetles, grasshoppers, inch worms ,crickets and either Dobson Fly or the pupa stage Hellgrammite. See Alder Fly section above.

BH Copper John, Brown Drake, Green Drake, Hi-Vis Gray Drake
Leadwing Coachman Wet Fly, Light Cahill (dry), Light Cahill nymph, Burnt Wing Yellow Drake.


Any time that you can be on the water is a good time. If you are looking for dry fly action, some times are better than others. March Browns and Gray Foxes can hatch as early as 11:00 AM. On many days a constant emergence will provide day long surface activity. March Brown Nymphs and traditional March Brown wet flies fish well into the early evening. Look for spinners in late afternoon.

The Sulphur hatch begins with a larger yellow/tan size #12 or #14. Light Hendrickson starts around the 3rd week of May and as the month progresses the Sulphurs’ get smaller (#16 – #18). Try a Pale Evening Dun. In general, the earlier larger Sulphur become active around 4:00 PM. As the days get longer the flies get smaller and their emergence moves later and later into the evening. During the seasonal peak of the Sulphur hatch, spinner falls of the Sulphur’s can be phenomenal. As evening approaches, shorten your leader and increase tippet size to prevent break-off’s. You can fish well into dark if you can handle the squadrons of bats that fill the sky feasting on the mayflies. Darkness is also the most active time for Mosquitos, so either stay in the water or cover yourself with a head net or lots of repellent as you move off the water and back to civilization.

Sulphur Dun, Sulphur Emerger, Cripple Emerger, Klinkhammer Emerger, mayfly and Spinner

Caddis can pop up at anytime of day, so be prepared with a basic Caddis selection (especially on the Housatonic and Naugatuck rivers).  Catch some samples and note the body wing colors and overall fly size.  Ant and beetles during the late morning and before the hatch can produce fish.  Streamers fished aggressively covering lots of water can catch big fish. Around the 2nd week of June, Bass season opens in NY,  In the mid-Hudson valley, to the Farmington river, look for Golden Drakes  in the 3rd and 4th week of June.

Golden Drake dry fly

Summer: June – August

Flies: (Trico’s and Terrestrials)

Trico Dry, dun, emerger, mayfly, parachute and spinner.

Water Conditions:

During good water years, stream flows will provide fish with deeper runs and pools for safety and feeding opportunities. During drought years, the CFS (cubic feet per second) flows become very low. Water temperatures will soar into the mid-70’s and/or higher on the non-tailwaters like the Housatonic. During summer, if the water temperature is above seventy, try bass or salt-water fishing, as almost any trout hooked and played will die.

Key Factors:

Stream flow and temperatures are the key factors. Good hatches of Trico’s will create some excellent fishing with size #22 – #26, in early morning, until around 9:00 AM or later on overcast days. The Farmington River, streams in the Croton system and Catskill tailwaters such as Esopus Creek can provide colder water and excellent hatches. Give fly fishing for bass a Try. Fish terrestrials and frog patterns at any time of the day, especially under bushes and trees where they usually fall into the water.


Look for Trico’s to begin in late June or early July. The Trico is a small mayfly that hatches in the early morning. The male and female are different sizes and colors. Mating swarms can be large, but the fish won’t start to feed until the spinners drop onto the water’s surface.

Trico Dry, Dun, emerger, mayfly, parachute and spinner.

Ants, grasshoppers, beetles, inch worms, and crickets are available to fish all summer long. Windy days blow more food into the water from streamside vegetation. Various species of Cahill continue to emerge. In early to mid-August, the White Fly mayfly hatches in the evening on Wappinger Creek,  the Ten Mile, Housatonic and upper Naugatuck are outstanding.

Fall: September -November

Water Conditions:

Sometime about the second week of August, the nights tend to get a bit cooler. Water temperatures begin to cool but water levels can be at summer drought lows. Fish are spooky in low clear water. Thunderstorms and heavy summer rains bring much-needed refreshment to New England streams.

Key Factors:

Water temperatures and stream flows are the critical factors. September and October are spawning season for wild Brook and Brown Trout populations. Fish in general are more voracious as they seek to put on weight for the long winter ahead. Fall Blue Winged Olives and flying ants generate some of the best fishing of the year.

Strategies and Flies:

Fall can be one of the best times to be out on the water. Fish are on the move again and more aggressive, as summer has passed and colder water dominates. Small Blue Winged Olives and related species can provide super dry fly activity. As in the early part of the spring (April -2nd week in May) fish during the pleasant part of the day. Leaves in the water begin to cause problems as they are easily hooked. Fall winds can play havoc on accurate casting so adjust your leader and position accordingly.  Midges should not be overlooked as they can provide excellent results into December. Streamers can be fished with confidence. Any streamer or stonefly with rubber legs fished in the fall in the Housatonic will get a 2nd or 3rd look and probably a strike, during the fall. If they aren’t working for you, adjust your stripping techniques so your offering is hitting all depths of the water, not just bouncing off the bottom. Most of the rivers and streams in Northwestern Connecticut  and eastern NY state are subject to flying ant hatches. The fishing can be out of this world if you have the right patterns. Always carry a few flying ant dries in your fly boxes. Brown, amber and dark gray with dun or clear brown wings in sizes #16 – #20 tend to give the best results. Remember to pickup and recast before your line begins to drag. Other terrestrials, in any size or species will also be effective. On the Housatonic, this is a great time for stink bugs, coffin flies and the Dobson Fly;  beetles in sizes #12 – #14, Chernobyl Ants, size #6 – #8, and Griffiths Gnat (during Midge activity) size #22-#24).

Chernobyl Ants
Black Chernobyl Ant, Soft-Hackle Coffin Fly, CDC Grifith’s Gnat, Hellgrammite, Stonefly with rubber legs.

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