In an effort to “match the hatch,” fly tiers have developed fly patterns to imitate just about every variation of insect a trout might eat. Why settle for a generic mayfly nymph when you can have a more precise imitation of hexagenia limbata.

hex fly for fly fishing
hex fly for fly fishing

The problem with this, however, is that there are now thousands upon thousands of fly patterns in existence. And for those who are new to the fly fishing game, this overwhelming number of fly options can spell trouble.

But before paralysis by analysis sets in, here’s a little secret that will help you get a better grip on the wide world of flies:

Trout in rivers and lakes throughout North America feed primarily on only four groups of insects: mayflies, caddisflies, midges, and stoneflies.

Yes, there are thousands of different fly patterns, but the vast majority are just different variations and imitations of the aforementioned bugs. And no, you don’t need exacting imitations for every insect species. As long as you select a fly that roughly resembles the natural in color, size, and body profile, you’ll be catching fish.

Mayfly Nymphs

Found in most, if not all, cold water lakes and streams, mayflies are an incredibly important food source for trout. When a mayfly hatch is going off, famous dry flies like the Adam’s or Quill Gordon can be used to seize the opportunity. But since mayflies, like other aquatic insects, spend the vast majority of their time underwater, imitations of mayfly nymphs outperform their dry fly counterparts more often than not.

Pheasant Tail Nymph
pheasant tail nymph a GOTO fly

Anytime you hear the words “Blue Winged Olive,” “Hexagenia,” “March Brown,” “Hendrickson,” or “Sulphur,” mayflies are around and these are the nymphs you’ll need:

  • Pheasant Tail Nymph, A very old English fly pattern that imitates a huge range of mayfly species’ nymphs, particularly blue wing olives and pale morning duns. Stock up on sizes 16 through 24.
  • Hare’s Ear Nymph, Another classic nymph that looks very buggy thanks to the spiky hare’s mask fur dubbing. You’ll find hare’s ear nymphs available in many different colors but stick with a few standbys including natural, olive, and black. Sizes 12 through 20 will imitate most mayfly nymphs you’ll encounter, but larger sizes of Hare’s Ear nymphs make a great stonefly imitation, so carry a few sizes 6 and 8 just in case.
  • Prince Nymph, More of an attractor pattern than a direct imitation, the Prince Nymph has a wide range of applications and is a great fly to use when you’re not sure what’s in the water. If you have a notion that mayfly nymphs are around, tie on a prince nymph in sizes 10 through 18 and fish it under an indicator.

Caddis Nymphs for Fly Fishing

Unlike mayflies which go straight from larva to winged adult, caddisflies go through a complete metamorphosis which includes a pupal stage before emerging. This extra lifecycle stage of caddisflies provides trout even more opportunities to feast. Luckily, matching a caddis nymph, regardless of life stage, isn’t difficult if you have the following flies. ?

green caddis
green caddis fly
  • Green Caddis Larva, Before they build their silken cocoons, caddisfly larva look like little caterpillars. There are color variations between the different species of caddisfly larva, but green is very prominent and always a safe bet. Keep a selection of sizes 14 through 18 on hand anytime you’re fishing caddis-rich waters.
  • Czech Nymphs, Bobeshes, a certain type of Czech nymphs used heavily by European and competition anglers, are another great imitation of caddisfly larva. Often tied with slim, sleek body profiles and lots of added weight, Czech nymphs drop through the water column very fast to get into the strike zone pronto. Go for sizes 8 through 18.
  • Deep Sparkle Pupa, After undergoing metamorphosis in cocoon-like cases, caddisflies leave their temporary shelters as pupa. In order to rise to the surface, gas bubbles form under the caddis pupa’s shell, a phenomenon which is effectively imitated with the iridescent material used in the Deep Sparkle Pupa nymph fly. Fish the Deep Sparkle Pupa in sizes 12 through 18 and make sure you have at least one tied on anytime you see caddisflies emerging.

Midge Nymphs

Midges are common in stillwaters ranging from small ponds and ditches to pristine mountain lakes. Tailwaters throughout the Western United States are also hotspots for midges, keeping resident trout well-fed year-round. Dry flies such as the Griffith’s Gnat are great during a hatch, but if you want to cash in on a trout’s midge-addiction, flies that imitate midge larva are what you want.

Here are three midge larva flies that work particularly well fished very slowly in stillwater and tailwaters:

  • Zebra Midge, This bare-bones bead-head fly is a spot-on imitation of midge larvae, which are also known as chironomids. There are lots of variations of the Zebra Midge, but make sure you have the basic black and silver along with red and silver. Throw in some emerger versions for good measure. Keep your box stocked with Zebra Midges in sizes 16 through 26 ? yes, 26 is ultra-small, but you’d be surprised how well these tiny flies attract big trout!
  • Brassie, This highly effective, super simple midge larva pattern sinks like a rock thanks to its copper body and bead head, making it perfect for fishing deep. The classic Brassie is tied with plain copper wire, but other colors including red, olive, and gray are available along with emerger versions. As with Zebra Midges, have a selection of Brassie nymphs in sizes 16 through 26.
  • Top Secret Midge, Another one for the box that you can pull out when trout are keyed into midges, particularly emerging midges. If Zebra Midges or Brassie nymphs fail you, tie on a Top Secret Midge to get the job done. Again, stick with this fly in sizes 16 to 26 and match your selection to the natural midges in the water you’re fishing.

Stonefly Nymphs

Requiring the cleanest, most highly oxygenated water, stoneflies aren’t nearly as widespread or prevalent as mayflies, caddisflies, or midges. But if you do happen to be fishing a river where stoneflies live, expect to find big healthy trout feasting on these prehistoric insects.

Here are two nymphs that will help you catch stonefly-seeking trout in a variety of conditions:

  • Pat’s Rubber Legs, This impressionistic fly looks basic and even a little silly, but it catches trout like a fiend. You’ll find Pat’s Rubber Legs in a range of colors to match the various species of stonefly from little yellow sallies to salmon flies. Stonefly nymphs can get very big, so grab a selection of Pat’s Rubber Legs in sizes 4 through 12.
  • Wired Stonefly, Sometimes you need a more direct imitation than Pat’s Rubber Legs, in which case the Wired Stonefly is a great choice. Being a very heavy fly, the Wired Stonefly is a great anchor fly on multi-fly nymph rigs whether fishing with an indicator or tight line. Sizes 4 through 12 will work in most situations.

Add A Few Worms and Eggs and You’re Set!

You’ve covered your bases with a selection of nymph flies that imitate the most prominent insects trout eat mayflies, caddisflies, midges, and stoneflies.

But before you trek to the stream, be sure to throw in a handful of ever-faithful San Juan Worms and an assortment of Glo Bugs and other egg-flies. These oddball flies might not fit perfectly in the “nymph” category of flies, but because they’re often fished just like more traditional nymphs, no nymph fly box is complete without them.

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