
Introduction
Fishing often has numerous variables that we cannot fix or control. Water level, temperature, bug activity, and weather are just a few variables that can impact your fishing trip. These can sometimes result in skunked outings and a long car ride home. The best anglers are able to adapt to the variables that are out of our control. I will highlight some of the tiny but mighty variables that impact an angler's day on the water when fishing subsurface techniques. These include weight regulation, fly selection, fish location, and the time of day.
Weight Regulation
Weight regulation is the most important part of nymph fishing that many anglers often ignore. Proper weight allows us to get our flies down to the fish, but still maintain a clean drift. Improper weight either causes us to be too deep or too shallow. Too much weight often brings snags and fouls our casting ability. Also, too much weight can cause an unnatural drift. Too light of weight will result in your presentation going over the fish. A fish will rarely bite a fly if it's not in the proper water column. It is usually not ideal to fish with the same amount of weight in every spot. Some spots have a similar current speed and depth, but most will have numerous differences that require a different weight approach. When fishing with a drop-shot technique, an angler can often get away with more weight than an in-line rig.
Fly Selection
There are an absurd number of different factors that go into selecting the right pattern for the moment. The most impactful in my experience has been size, color, and the use of beads or specific materials. On any given day, a change to one of these variables can have a massive impact on fishing. I typically like to adopt a 3, 3, 1 rule. I rarely allow myself to leave the house without having at least 3 sizes of each fly, 3 colors of each pattern, and 1 variation that has a unique or differing characteristic. This covers most of my bases and limits the number of outings I have where I don't have the hot pattern.
Size
Picking the right size fly can sometimes be tricky depending on the location where you fishing. On a freestone trout stream, size isn't always an important factor. Less technical streams put less strain on fly selection and more on proper casting and mending techniques. At the same time, the right fly pattern is still an important piece of the puzzle. Highly pressured streams and tailwaters below dams often require smaller patterns and put greater emphasis on both fly selection and presentation. On a freestone river, I typically like to start with a nymph that is in the middle of the size run. For example, a Yellow Sally Nymph usually runs from a size 14 down to a size 18. I would start with a size 16 in this situation in most moments. On a tailwater stream, I would start with a size 18 instead. I fish smaller on tailwater streams to make my presentation as natural as possible.
Color
While color isn't as important as size, color still plays an important role in having the right fly pattern for the occasion. Some insects can have a wide variety of colors and sizes, while others are only one color. Starting with the most prevalent color is usually a solid choice when initially wetting your line. Knowing the different hatches for your river will help greatly with choosing the right color. I will be covering entomology in next week's post. Brown, black, gray, and olive are all popular colors that can cover different insect groups and spectrums. Some patterns like blue-wing olives are all going to be the same color. This eliminates the guessing game, which can be nice. Mottled colors are almost always a good idea, especially when fishing stoneflies. I recommend changing colors after trying multiple sizes of one color. When determining fly color, Flipping over river rocks and trying to find insects is a good idea. Either way, stick with the earth tones if you are uncertain what color you should fish. You will know once you find the right color.
Unique Fly Characteristics
Some other characteristics of fly patterns that can impact performance include
Flash Materials
Bead Heads
Flash Materials:
Flies made with flash can often be more productive than those without it. An example of this would be a Flashback Pheasant Tail vs a regular Pheasant Tail fly. The pearl flash represents the wing case of the insect, which can increase the appeal depending on the circumstances.
Flashback Peasant Tail Pheasant Tail


Having a fly with flash can often attract fish and result in way more hookups. Flash works on some rivers better than others. Having flies with flash can make or break your day. Flash is usually equally effective on tailwaters and freestone streams. Flashy flies are more effective when the sun is on the water.
Bead Head Patterns
Bead head patterns have become extremely popular over the last decade. Beads allow flies to sink quicker and get to the fish faster. These are usually made in either brass or tungsten. Brass beads sink slower but is much cheaper. Tungsten sinks quickly but is quite expensive. Either way, beads can help catch fish that are hugging the bottom, or hanging in deep water. Bright Beads also act as attractors, which fish very well on certain patterns. I always recommend having beaded flies in your box to help catch fish in deeper water and attract fish to your setup.
Time of Day
Time of day is an underrated aspect of fishing that can make or break your trip. Barometric pressure, air and water temperature, and other factors make certain times of the day far better for fish. Low barometric pressure is often associated with making fish more lethargic, which slows down the fishing. Higher pressure increases fish activity, but fishing still is usually average fishing. Often having pressure in the middle range is much more advantageous to consistent fishing. At the same time, quick raises and drops in pressure can indicate to the fish that a storm is coming. This triggers their instinct to feed. This is why some of the best fishing can happen right before a storm comes in. Temperature is probably the most important indicator to determine what time to fish. I normally try to target my fishing times when the most bug activity is going to occur. Usually, the more bugs that are hatching, the more likely the fish are feeding. This correlates to the warmest times of the day in the winter and spring, while fishing in the summer can vary wildly depending on the hatch. Usually, the best hatches in the hottest months of the year happen in the morning and evenings. Water temperature dictates insect hatches and the energy level of the trout. Trout are more sluggish during both high and low-water temperature extremes. When temperatures are between 45-58 degrees, trout will be the most active. Winter or spring days when the weather warms up dramatically are usually awesome days to fish, while cooler days in the hot months are great days to fish.
Overall, regulating weight properly and fly selection improvements will make anglers more effective in nymph fishing. Small details are often more important than people think. The world of fly fishing punishes those who fail to see the small details and rewards those who adapt and change to the small details. Time of day can also often dictate your success on the water. Every day is different in the world of fishing.
Wow, what a wealth of information! Well done!!!