Anglers are always looking for an edge to catch more fish. A fish finder is an extremely effective tool, but only if you know how to use one. Whether you are new to fishing, new to a fish finder, or are simply using a boat with one it it, this guide should help you get the most out of your fishing tool and teach you exactly how to use a fish finder.
What is Fish Finder?
Fish finders are SONAR (SOund NAvigation RAnging) devices. That means they use sound waves emitted from the device to identify objects below your boat.
The sound omitted from the device travels quickly downwards (about 1 mile per second) travels to the bottom, or to objects in between the bottom of the body of water, and are reflected back towards your device. When the sound wave returns back to the device, it sends another pulse, and it continuously repeats this process.
By measuring the time it takes for the sound wave to return, and how strong that sound wave is, the device, using a computer and software can judge depths of objects. It converts these sound waves into electrical signals to display results in a readable format for fisherman and boaters.
This is a very brief and simple explanation, but feel free to check out this guide for a deeper understanding of how SONAR works.
Fish finders can be pretty expensive. You’ll find dozens of options in different price ranges. We aren’t going in depth on how to choose a fish finder in this article, but you may be interested in finding a device on a modest budget. Check out this guide from FishingPanel to see a quality list under $500.
Need To Know Information
What You See Isn’t Necessarily Directly Below You
What you see on the screen doesn’t mean it is directly below you. Sonar emits sound in a cone pattern, so the results can be not directly below you. Don’t let your screen fool you on this.
Sound doesn’t travel in one direct line. It is a wave that expands. Therefore, the deeper the water, the wider range your fish finder is scanning.
Most scanners allow you to adjust the angle of scanning to show more or less water by adjusting the frequency of the waves being emitted. A wide scan (above 40 degrees) will allow you to scan large areas, and get good information about depth, and bottom strcutures, but a wider scan will have less detail. Wider scans work well in shallower waters since a narrow scan won’t be able to see much below you in shallow water.
In deeper water, a narrow scan is more common. If you need to pinpoint depth below the boat, of find fish directly below the boat, a narrow scan setting will likely be used.
Fish Finders Can Find Other Objects & Have Blind Zones
Because of reflections of sound waves near the surface, and other debris often near the surface, it may be difficult to get good results from your fish finder in the first meter or so below the the fish finder device.
The Scrolling Of Your Fish Finder Doesn’t Mean You Or Fish Are Moving
What you see on the screen is real time and historical scans from your device. If you aren’t moving at all, the SONAR will still show results scrolling passed, that’s because it is continuously sending out sound waves, and displaying the results on your screen. One fish may show up repeatedly if it is still in range of your SONAR.
Thicker / More Colorful / More Dense Results Indicate Surface Differences
When your results are very distinct solid lines, that indicates a harder bottom is below. Rocky bottoms will display more clearly, while a muddy bottom will have weaker, and thinner results. This is important to understand as different bottoms can change your fishing tactics and ability to catch fish.
Arches Mean Fish
In many cases, a fish won’t be in your SONARs viewing zone the entire time. It will come in, and out of the zone, or your boat will pass over the fish. This action creates an arch like feature on your device.
This therefore can help you understand a little bit more about the fish on your screen:
- If you aren’t moving, and arch will only occur if the fish is moving. If the fish as staying still, and you are moving over it, you’ll also get an arch.
- If a fish is staying under your device, you’ll see a line, not an arch.
- A full arch indicates the fish went fully threw your SONAR zone.
- If a fish only goes through part of the zone, you’ll likely only see a partial arch, or a small line.
- Long doesn’t mean big, that means they were in your zone for a while. Thick line means big.
This is a fantastic video for better understanding of all you should know about fish finders:
How to Use a Fish Finder?
Step 1: Learn More About The Fish Finder at the Manual
The first thing to do is to read the manual. We know…this sounds frustrating, but you’ll likely learn a lot about your device, as well as features that you may have not been aware of. Always give your device a Google search. Look for an instructional video on YouTube, or the manufacturers website. These visual trainings are often the best way to quickly learn how to use your device.
We recommend watching a video while you are on your boat, or while you have the device in front of you to learn as much as possible.
Here is a general instructional video that does a great job of explaining common features on most fish finders, as well as best practices for getting the best results out of your device:
Step 2: Understand the Location of the Basic Buttons
In most cases, the buttons remain at the left or right corner of the tool. Have a look at the buttons and understand their functions. You may have a touch screen as well. If there are buttons you don’t understand, you should look them up in the manual or online. It is better to research ahead of time, so that when you are out in the field for the first time, the learning process is much faster.
Step 3: Understand The Right to Left Display
Now it’s time to read the display using SONAR. The finder shows the recent data on the screen’s right and pushes old data to the left. In the case of a stationary boat, the display cycle goes right to the left, but you will see only one area. That’s because the SONAR is continuously reading below you. Not showing a moving bottom. Always remember this fact!
Step 4:Get Your Settings Right
Often times, beginners can just get away with utilizing the auto settings function to calibrate everything, and show the bottom properly. You can manually change these settings to optimize performance. We recommend viewing the video above for steps on how to do that.
Be sure to select the proper angle settings for your depth and what you are looking to accomplish. In shallow water, you’ll want a wider range, say 40-60 degrees while in deeper water, you may want to reduce that angle significantly.
Step 5: Adjusting The Display
Zoom in or Zoom Out: Need to know more data about the activity in a certain depth? You can zoom in to get a more accurate image.
Color Adjustment: You can change the display and lettering color. Some display shows black letterings at the white display. Not all fish finders have colored displays, but the ones that do make reading them a bit easier. And different color schemes can be easier to read than others. Choose what works best for you.
Fish Symbols Instead of Dots/ Arches: Some fish finders come with advanced features. If you are unfamiliar with dots or arches, you can change the symbols to fish icons. Change them if you are uncomfortable, but we recommend sticking with arches as fish symbols take away details that can give you greater insight.
Step 6: Locating The Fish
As we discussed earlier, fish are often going to be arches suspended in the water, or with a gap just above the bottom. Straight lines, or half arches may also be fish in the water within your SONAR range. Longer lines or arches does not mean larger fish. Larger fish have thicker (more height) than smaller fish.
Max DesMarais is the founder of hikingandfishing.com. He has a passion for the outdoors and making outdoor education and adventure more accessible. Max is a published author for various outdoor adventure, travel, and marketing websites. He is an experienced hiker, backpacker, fly fisherman, trail runner, and spends his free time in the outdoors. These adventures allow him to test gear, learn new skills, and experience new places so that he can educate others. Max grew up hiking all around New Hampshire and New England. He became obsessed with the New Hampshire mountains, and the NH 48, where he guided hikes and trail runs in the White Mountains. Since moving out west, Max has continued his frequent adventures in the mountains, always testing gear, learning skills, gaining experience, and building his endurance for outdoor sports. You can read more about his experience here: hikingandfishing/about