Fly Fishing Tips | Understanding a Trout's Diet

The Most Important Fly Fishing Tip is to Know What Trout Eat

FLY FISHING | TROUT FISHING

April 29, 2016 by Phil Manning

​Trout eat many different things. Exactly what is in their diet depends on a number of factors including waterway health (availability), season and geographical location. Most important to a trout's diet and thus to us as fly fishing anglers are the aquatic insects that spend much of their life-cycle underwater only to transform through the water's surface into flying, mating adult species. Without understanding these species well, all the fly fishing tips in the world are not going to help you be a better angler.

Trout eat mainly aquatic insects, terrestrial insects, crustaceans and other fish species. Their diet varies based on season and waterway. Fly anglers are successful when they can mimic a trout's preferred forage giving the time of year and the location your are fishing.

Streams in Pennsylvania will be packed all the way up until the end of May. Between opening day of trout fishing season, additional trout stockings and the prolific hatches, anglers of all kinds will be out fishing. However, Pennsylvania fly fishing anglers have a few special places to sneak off too. There are many special regulation trout streams where some of the best fly fishing in Pennsylvania takes place. The key to catching rising, and even bottom dwelling browns, is to understand the most important fly fishing tip, a trout's diet.

Fly Fishing Tip #1 - Match the Hatch

​Aquatic insects spend most of their lives underwater. The thrill for many fly fishing anglers in Pennsylvania is the few moments these species escape to the air. This movement exposes the insects to predators like birds and fish, particularly cunning trout waiting just below the surface in anticipation. Huge swarms of hatching insects put trout in a feeding frenzy and the fish focus in, often unlikely to be landed on any other bait. Successful fly anglers "match the hatch" by choosing the correct size, type and presentation of the hatching insects. If done successfully, each cast of the fly, often mimicking a mayfly or caddisfly, is an opportunity at catching a feeding trout.

Knowing the insects hatching on one of the many Pennsylvania streams is part of the challenge to dry fly fishing. Most times, the difference between successful evenings and only landing one or two trout is based on size. This is where understanding exactly what the trout are eating comes in as one of the most important fly fishing tips. Match the fly as close as you can if unsure of the species but more importantly match the size for more hook ups on the surface.

Best Flies for Trout in PA | Dry Flies

Every stream has different variations and even completely different populations of insects. Because of this, one can get overwhelmed with trying to know and carry all the different variations of dry flies for every situation on trout streams in Pennsylvania. There are, however, a few top dry flies for matching the hatch every angler should have on hand at all time. Fly fishing tip #1 - make sure you have these dry flies in multiple sizes.

1. Blue-Winged Olives - A common mayfly across all of Pennsylvania. Hatches are most prolific in the spring and fall but they can be found hatching throughout the year. Keep stocked in size 16-18.
2. Elk Hair Caddis - The caddis hatches are another one to mark on the PA fly fishing hatch chart each year. Stick to the basics and stock Tan in 14-18 size for most fly fishing situations.
3. Black Ant - Although not a hatching insect, the black ant can be one of the best flies for trout in PA during the summer. When other insects have long stopped hatching, the ant dry fly pattern can produce some great surface action.

The Trout's Nymph Diet

Trout feed on aquatic insects below the water, although not as extravagant as dry fly fishing to an angler, perhaps more than they feed on the surface. Fish can take nymphs throughout the course of a day by catching stream driven insects in the water column or bottom feeding through rocks and gravel in riffles. Nymphing is more reliable than dry fly fishing for trout because it allows you more options to fish (think time of year nymphs, streamers, sow bugs, terrestrials, etc.). Fish are also feeding underwater throughout the day, regardless of hatching insects or not. Take time as you get to the water to examine the underside of rocks in the stream. This will give you an idea of the aquatic insects in that area of water. 

Best Flies for Trout in PA | Nymphs

The nymph can catch trout at any time of the year. Nymph fishing for trout hardly excites most PA fly fishing anglers but ask any PA fly fishing guide and they will tell you nymph fishing produces no matter what time of year. Here are three nymphs everyone has to have in their Tacky fly fishing box.

1. Beadhead Pheasant Tail - Can be fished anytime and anywhere to catch trout on a fly rod. The beadhead version helps to get it to the bottom and provides a slight shine to entice distance trout. The best sizes for most situations are 14-18.
2. Green Weenie - A simple fly pattern but extremely effective. This fly can be dead drifted anytime of the year but also works well during the summer. Sizes from 12-16 will be enough for just about any trout stream in PA.
3. Hare's Ear - Another all-around nymph that does not specifically imitate a certain insect but it just works. Fish in sizes 14-18 with or without a beadhead.

Spring is here in much of the country meaning fly fishing across Pennsylvania is starting its upward path to its peak. Understanding a trout's diet both above and below water probably the most important fly fishing tip. Knowing what they are feeding on and why will only help increase your success on the water.