Fly fishing, a skillful blend of patience and technique, often presents a myriad of challenges, with one of the most critical being the depth at which your fly is presented. One of the most common mistakes made by anglers, beginners and seasoned pros alike, is not getting their fly deep enough. This error can drastically reduce the effectiveness of a day on the water, often leaving anglers puzzled and frustrated. Sadly, it is repeated that you need to have your flies to the correct depth but for some reason, it is rarely considered by most anglers. Instead, they focus on the particular fly, size of the tippet, perfect drift, etc. These are all great but when you talk to most guides or successful anglers the first thing they adjust or suggest to adjust is weight. They want to achieve depth and know that has the largest effect on success. I have a guide friend Chris, who constantly says, “Let me add some more weight.” Another friend Todd, fishes golden stones everywhere we go and the only thing he seems to ever change is weight. Another friend of mine constantly changes his euro rig and all he ever talks about is bead size. All of these guys are fantastic anglers and I feel their obsession with weight and depth every time I go out with them. It is like they are manic and can’t think of any other way to succeed. I want to cover why depth matters and highlight a few areas for you.
Number one is that depth addresses fish behavior. Different species of fish inhabit varying depths depending on factors like water temperature, time of year, and food sources. Many species, especially larger and more elusive ones, tend to stay in deeper waters. By not reaching these depths, you miss a significant portion of their target species. It’s getting to the correct depth that matters.
Next, let’s consider what natural food source presentation looks like. In their natural habitat, prey items that fish feed on often originate from or spend time in deeper waters. Food presented at shallower depths can appear unnatural, reducing the likelihood of a catch. Let's use the example of aquatic insects. The majority of aquatic insects live and move on the substrates and are naturally presented to fish lower in the water column.
That brings up our next topic of environmental conditions for our targets. Factors such as water clarity, light penetration, and temperature gradients play a crucial role in how deep fish will be found. Bright light, for example, often drives fish to deeper, darker waters. Cooler temperatures are in the deeper holes. Hiding spots from predators are in deeper less clear positions. You can start to see the trend. Most importantly, most fish reside along the substrate where current is influenced and there are resting or holding positions more suitable for fish.
Now we know that typically fish prefer deeper water, they see their food naturally in the deepest portions of water and lastly, they have cooler more comfortable water with less current to be influenced by. That to me sounds like home and the first thing I want to do is blow up a fish's home with a nicely drifted fly for them to eat. My wrestling coach used to always talk about how we were going into the other team’s home on away matches and it always got me excited to disrupt them in their comfort zone. I feel the same way now with fly fishing. I want to always be in their home making them uncomfortable in my net.
Conversely, fish with an attitude that there are consequences of shallow fishing and you’ll see the effects by catching more fish and staying out of perceived trouble. I think most anglers cast to cast and don’t think about the consequences. Fishing is fun, fishing is relaxing, fishing is this or that. The reality is you are fishing if you are blind casting and not thinking of consequences. Instead, avoid the consequences and start catching instead of fishing all the time.
For example, the first consequence is reduced catch rates leading to the former statement of more fishing and less catching. Fishing at inadequate depths often results in fewer bites and, consequently, a lesser catch. Don’t waste time prospecting where there isn’t much gold.
When you are at the incorrect depth you can often be targeting the wrong species. By fishing at the wrong depth, it is common that you might inadvertently target species that you aren't interested in. In saltwater fishing, this is all too common. You end up with bycatch scenarios instead of consistently presenting and hooking your targets.
“Time isn’t cheap,” is what my first boss used to tell me. He was a small chubby Italian immigrant and I was still in high school. I would clean, hem, and press tuxedos. He would hawk the clock and my efforts every minute of the day and always told me how to do things faster. He had more tricks in his bag than a magician. We should be like that when fishing. We all could use more time on the water. Even more so we want to execute more effectively when we do have time. Wasted efforts are an angler’s nightmare in my opinion. Anglers may spend hours without success, not realizing that a simple depth adjustment could yield better results. I see this all the time on the Provo River in Utah. Someone will find a hole and float a bobber through it hundreds of times before adjusting depth. More commonly they will change flies about 30 times. If they changed depth they would likely see success. Instead, they have rigor mortis of the legs and are dead-set believing that the fish just aren’t eating. “Hawgwash,” as my grandmother would say.
Hopefully, by now you understand that depth is a serious concern for anglers and most make not achieving depth their number one mistake. That being the case, let's talk about adjusting for depth and ensuring your fly fishing success. I’m going to walk through several ways to obtain depth. A friend once toldn me, “if you aren’t hanging up then you aren’t in the right location.” I challenge you to go out and fish deeper the next 2 or 3 times and see the benefits.
I’m going to start with some of the basics for achieving depth. Even though they may be obvious they are often overlooked. Choosing the right fly line is a great example. I fished the White River with a guide and he only used weighted lines and unweighted flies. He wanted the flies to move smoothly like a fish but knew he had to get down. Needless to say, he was a master when it came to sink rates. Using fly lines with varying sink rates to target different depths is easy to do. There are countdown methods, etc. to complement the lines. When you think about streamer fishing or stillwater fishing fast-sinking lines are essential for reaching deeper waters.
Using sinking leaders and tippets can have a tremendous impact on achieving depth and achieving it quickly. Incorporating leaders and tippets that sink can help in getting your fly down to the desired depth, especially in faster currents. Two adjustments can be made that will seriously affect achieving depth. One is to use a fluorocarbon line because it has a higher density and will sink in water and monofilament is the opposite. Two, reduce the size. Size does matter and the smaller the better. It’s hard to believe that the micro-level measurements of a tippet or leader affect a drift and sinking to depth. However, it is critical. Let’s use the example of cutting a tomato. If you cut a tomato with a sharp knife it goes right through. However, a dull knife never wants to pierce the skin and smushes the tomato pushing it out of the way, slowing you down from making that delicious BLT. You want your leader to be thin like a razor-sharp blade so you can cut the water instead of pushing it out of the way and slowing everything down.
Now don’t forget to address the number one overlooked way of achieving depth. Extending your line. If you want depth then you need to have the appropriate length of line to do that. That means extending your tippet on a nymph rig so the butt end of the leader isn’t in the water affecting depth with drag as discussed above. Longer dropper lines are another example where you can do this. I see people in 3 feet of water fishing an 8-inch dropper off the bend and the fly has a tiny bead on it. If the fish aren’t feeding near the surface you are dragging a dropper for most likely no reason at all. Instead, increase the length of the dropper and get the depth you need. Sometimes that is a 4 or 5-foot dropper.
Now that lines are addressed and you have the physical capability of achieving depth, what can be added to achieve depth and achieve it fast? Number one for me would have to be weighted flies. I’m a pretty firm believer that the majority of fish don’t care much about how flies look as long as they look close enough. More importantly, they care about how easy it is to get in their mouth. Putting flies in the right direction so there isn’t a chase or much movement is extremely effective. Fishing flies with tungsten beads, thinner bodies, etc. all help them achieve depth. You could write an entire article on how flies achieve depth and the micro difference between each fly type and how that is affected but we are looking to address a large-scale issue. The issue is you aren’t getting down. Start with heavy thin flies and when you are regularly feeling the bottom then start working back up the chain of flies for lighter and or slower sinking types. Going the other way you never know you are deep enough until you’ve reached the bottom and likely spooked all the fish.
Lead! The dreaded word in a lot of anglers' vocabulary. Putting lead or split shots on and off your line is like going to the dentist. We have to go and if there is a time for change it sucks. Personally, I don’t mind getting it on but getting it off is a pain in the butt. I have recently moved to Loon’s Deep Soft Weight which is a putty and is easily applied. Getting it cold by dipping it in the water before casting hardens it up and keeps it from coming off. The stuff has been a lifesaver for me. Regardless of all the pain, split shots can be super effective for adding or reducing weight. I prefer using multiple smaller pieces so I can micro-adjust. They also tend to slink over substrate versus larger pieces that act like chalk stones an wedge into crevasses and cause you to break off.
Using indicators can be frowned on by purists but there are more fish caught via indicator than just about any other style. Why? They work! The thing about indicator fishing is changing depth and you can do it a few ways. One is with a mend and we will talk about that in a bit so let’s skip that. Second, is changing the length of the line below the indicator. Lastly is adding weight to your indicator rig or setup.
Length of the line below your indicator is a common mistake and I do see people adjust this. The difficulty I see is that most anglers look at the standard formula of one and a half times the depth and apply that to their leader. If you haven’t heard of this before it is a simple formula to understand how long your leader should be. First, determine the average depth you will be fishing take that number, and build your leader to one and a half of its length to achieve the appropriate length of your leader. For example, I intend to fish water that is 3 feet deep on average so my leader length should be 3*1.5 = 4.5. A four-and-a-half-foot length is correct. The giant mistake is that they look at leader length as the length of the leader's connection to the end of the leader. Instead, it is the length of the leader material and size you want to be fishing plus 8 inches or so. Otherwise, you end up fishing the butt section of the leader which will affect your drag and depth. Rather the line below your indicator should all be as thin as possible and the length of that section should match your calculation which is 4.5 feet per the example above.
I’m stacking the scenarios here if you haven’t caught on yet. Now that we have the line set, the leader set then you start adding weight. Just like above you can add flies for weight or add split shots. Either one will work. Just make sure that your flies are ticking along the bottom every once in a while.
Mending line is all about controlling drag and depth. This is critically important with an indicator. Here is a YouTube Video to demonstrate how to achieve depth with an indicator via a mend.
Additionally, because mending is so critical I created an entire article around how to and why you need to effectively mend your line. Mending How to Think About it When Fly Fishing | Fly Fishing Insider Podcast
Casting is the last I will address because it can often be the most technical. However, it is also one of the more effective ways. For example, drop any fly in the water and it sinks directly to the bottom. Add tippet and it takes a little longer so by adjusting casts we can do the same thing. Cast further above your fishing target to allow your flies to drift and drop to the correct achievable depth with more time. Very simple if you need to get to three feet of depth and it takes 6 feet to do that your flies better land at least 6 feet above where you think the fish are so the flies can achieve depth in time and the fish can see it.
Lastly is casting to drive your flies into the water. This is often called an Upper Downer cast coined by Joe Humphrey. Others may call it an impact cast or a driving cast. Either way, the technique can be described as an overhead cast where the rod tip finishes high and slowly descends. The importance of finishing high is to overpower your cast so your flies extend and land in the water first. The sight of the flies landing first is your first indication the second is that they are landing with force. The Upper Downer cast allows you to shoot the flies and have them hit the water with force so they drive to depth versus sink. That driving helps you achieve depth almost immediately.
Achieving the correct depth is a dynamic process that varies depending on numerous factors. That is not to say that all fish sit at depth. However, it is far more common for fish to be at depth than to be surfing mid-column or top feeding. By understanding and implementing these adjustments, you can significantly increase your chances of a successful and rewarding experience of catching versus fishing.
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By Christian Bacasa
Host of the Fly Fishing Insider Podcast
www.ffipodcast.com
@flyfishinginsiderpodcast
@dupeafish
