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How Does A Fish Finder Work | A Complete and Detailed Guide

You must be searching for an answer to a well-known question, how does a fish finder work? If that’s the case, then your search ends here. In this article, we’ll educate you about the basic concepts of fish finders and how they work. We will also cover the installation process, brands, and types of fish finders. At the end of the article, you will be an expert on this fancy fishing accessory. So, let’s start reading. 

How Does A Fish Finder Work

How Does a Fish Finder Work & What It Is

A Fish Finder is a fancy fishing accessory made for searching for fish underwater. If you’re out on a kayak fishing trip in deep waters, then you’ll need more than a pair of best-polarized sunglasses to look for a wish underwater. You have to understand what it is before getting to the answer to “How Does A Fish Finder Work.”

The fish finders will do a better job in searching for fish. Moreover, with the help of this fantastic fishing accessory, you’ll be able to find a perfect fishing spot in no time. It’s like a game-changer. It makes fishing very easy for anglers. 

This brilliant electronic device is made up of two parts: a display and a transducer. The display of the fish finder is installed in the fishing boat or a kayak. The transducer is an underwater sensor that searches for the fish and sends information to the display. 



Fish finder’s display is just a standard screen. It has enough computing power to receive input in the form of raw data from the transducer, convert it into useful information, and give output by showing the meaningful data on the screen. 


The transducer is the heart and soul of a fish finder. This fishing accessory’s main component works straightforwardly by sending sound waves into water depths. When it hits a fish, the transducer measures the size and depth. After completing the measurements, the transducer sends that information to the display. 


Note: the sonar waves(sound waves) can not recognize the difference between fish and other objects. That means any object that comes in the way of sound waves will be picked up and displayed on the screen. So, you can use a fish finder for finding not only fish but also other objects. 


Many modern fish finders feature GPS. It can chart your position and track on the map. At the present time, the Modern fish finders feature two types of GPS receivers; Internal and External. Both of them are good at their jobs, but the best is an External GPS receiver. The external receiver can show heading direction even at a light speed. In short, they are more accurate. 


All in all, the GPS fish finders come in very handy. It allows you to navigate correctly. Even more, it helps you find better spots for fishing and make waypoints to be able to return to the same places.  

Types of Fish Finders

If you are looking for an answer to “How Does a Fish Finder Work,” you also need to know types. There are three main types of this fancy fishing equipment:

  • 2D Fish Finder
  • Downscan Fish Finder
  • Sidescan Fish Finder

Many fish finders use a combination of different technologies to locate fish. You might get confused about the type of those products. In order to clear your head from such confusion, you must know that the primary function of every kind of fish finder varies. 

Just like every other product in the world, all three types of fish finders have advantages and disadvantages. No one is better than others; every type has its pros and cons that decide their most suitable application. 

2D Fish Finder

2D Fish Finder

The 2D Fish Finder is widely known as the traditional fish finder. It has a black and white screen, with the image scrolling from right to left. You can say it has a rough texture. Its display is like the old sonar detectors. 

How does It Work

Indeed, the 2D Fish Finder doesn’t have the best display, but it works remarkably well. It uses cone-shaped beams for reading the depth of water. The angle of the cone depends upon the frequency. That means a significant frequency has more comprehensive cons and a large coverage area, but a minor frequency has fine details. 

The 2D fish finder constantly takes the data from the transducer and shows output on the screen. The newest readings appear on the right side by moving the older data to the left. Let’s say you’re sitting still, and the kayak is not moving; it will show the same depth with the exact flat bottom. However, the scenes will change drastically when a larger fish swims through the cone(coverage area of the sonar). An arc will appear on the screen, showing the position of the fish. You’ll ready your equipment and attempt to catch it. 

Downscan Fish Finder

Downscan Fish Finder

 The Downscan Fish Finders are getting popular nowadays. That’s because they are cheap and easy to read. It provides a photorealistic display which makes a lot of things easier. Moreover, the vivid picture on the display screen is very clear and provides a perfect representation of what’s underneath. However, the coverage area of this kind of fish finder is very narrow and not adjustable. That makes it suitable for only shallow waters. 

How Does It Work

How does a Downscan Fish Finder work? The answer to this question is, it works in the same way as 2D fish finders, but there’s a difference in display and a few other things. The fish looks like an arc, only smaller in size as compared to 2D fish finders. That is due to the down beam that is a narrow slice of the water column. The hard bottom is effortless to see in this display. It will look brighter than the soft bottom, with a thicker band of color below. 

Sidescan Fish Finder

Sidescan Fish Finder

We saved the best for the last. The third and best kind of fish finder is Sidescan. If you’re a fan of perfect display(High Resolution), then this one’s for you. Even more, it has the ability to cover large areas. That makes this the best choice for deep waters. The downside of Sidescan fish finder is the cost. It usually costs more than 2D and Downscan fish finders. 

How Does It Work

Unlike the other kinds of Fish Finders, the Sidescan works differently. The primary difference is that it sends a narrow beam in the water, straight down and side-to-side. The display of the Sidescan fish finder receives a two-dimensional signal. That makes the output more detailed than the previous two kinds. Furthermore, the high-frequency transducer sends better resolution data. These qualities of Sidescaner make it better than the other two, but of course, if you can afford it. 

How To Read A Fish Finder

Fish finders are a handy tool, but only if you can read them. It will offer many advantages. Reading a fish finder will be very useful for choosing bait and other equipment. They can also help you in avoiding snags. Reading it won’t be as easy as reading a statement, but it won’t be difficult either. It will give you a rough estimate of the depth and the shape of the bottom surface. 

Undoubtedly, looking at a fish finder display is not like watching a video. The imaging sonar makes a picture that needs to be understood and interpreted. As mentioned earlier, it is not very easy to read a fish finder. Newbies don’t know what they are seeing and get confused. 

If you are a newbie like many others who can not read fish finders properly, you need a new gadget that offers Fish-ID technology. Many new fish finders feature this technology to make the job effortless. The Fish-ID will replace the image on your display with a fish icon. Moreover, it can differentiate between fish and other objects by showing other icons. 

How To Read A Fish Finder

Average Price And Difference Between Expensive And Cheap

There are hundreds of Fish Finders available in the market, just like other products. They range from $40 to a thousand dollars, depending upon their quality. It’s simple; money will buy you excellent products. 

There is a massive difference between a fish finder of $50 and $1000. The low-range models will provide you tiny details. They will give you rough estimates, but they can also be very useful if you understand them. The mid-range models are better. They pick up more activity and update more quickly. Even more, they provide accurate details. The premium models are the best. They update quickly, have more coverage area, and provide accurate details. Besides, they can also differentiate between the types of fish and give perfect estimates of their size and depth. 

In short, money buys you better quality. If you’re a rich person, then you should purchase premium products. They have more features to offer than listed above. You’ll be amazed by the things a premium fish finder can do. 

How To Install A Fish Finder

Installing a Fish Finder is not a confusing job. It is something you have to tackle in order to get started. Different models may have other installation processes, but the idea remains the same. 

In this section of our article, we will educate you about the procedure of installation and necessary tools. Follow these steps, and you will easily install your Fish Finder,

How To Install A Fish Finder

Connection Layout

The fish finder is an electronic device, and it does not operate on batteries. You have to connect it to a power source like 95% of other electronic devices. Two cables(positive and negative) must be connected to the battery you have in your kayak or boat. 

There’s one more connection that connects the fish finder display to the transducer. This connection passes the SONAR information. You can add as many devices as you want to your fish finder, but the basic installation requirements are these two connections. 

The Binnacle Mount

The binnacle mount is the mount of a fish finder. The first thing you have to do is find a perfect spot for it. It’ll be better if your fish finder is at your eye level, so you can easily note the readings and comfortably interpret them. 

When you’re done choosing the right spot, make sure it does not get in the way of other navigation devices, and there should be enough space for wiring and stuff. Now that you’re done with pre-mounting things, it’s time for the actual job. 

Drill holes for screwing it on and for the wiring purpose as well. Make sure that the holes are big enough for wires and screws. Install your fish finder and wire it correctly. That’s it. No big deal, right? 

Top 3 Best Fish Finders Available In The Market

As I mentioned before, there are hundreds of products available in the market. The increasing demand for Fish Finders forced the manufacturers to provide better quality at a sensible price. Just searching for an answer to “How Does a Fish Finder Work” won’t be of much help. Despite all the advantages of competition, it also made it difficult to choose between hundreds of products. Luckily, we made a list of the top 3 best fish finders available in the market. I’m sure you’ll find them value-providing products. Let’s get on with it. 

1. Garmin Echomap UHD 73s

Garmin Echomap UHD 73s

The Garmin Echomap is one of the best fish finders available in the market today. It provides lots of features at a reasonable price, and the best things about this product are the built-in Wi-fi and 7-inch touchscreen. 

This fantastic product boasts SideVu and ClearVu with CHIRP. The Ultra HD transducer, GT5UHD-TM, is responsible for that. It is a complete fish finder that features everything an angler would like to have. It comes with built-in maps, an 800*480 screen, a High-wide sonar, a clear image, and many more. 

If you’re wondering for a perfect mapping Fish Finder, then Garmin Echomap UHD is for you. This product comes with pre-installed LakeVu maps that cover an extended area. It also comes with a microSD card slot for more help. This is the best you’ll have.

2. Humminbird Helix 7 CHIRP

Humminbird Helix 7 CHIRP

If you’re a fan of great Side and Down imaging, the Helix 7 CHIRP is the perfect option for you. It features an attractive choice of Lakemaster chip for maps. It is undeniably, one of the best value-for-money fish finders available in the market today. 

The Helix 7 features a new Spectrum CHIRP 2D sonar which is more than impressive. It works brilliantly. The MEGA SI is also an excellent feature that makes the product special. It also features High-wide CHIRP sonar, making it one of the top-rated of its category. 

The Helix 7 also comes with a microSD card slot for Lakemaster chip and Autochart live. A bright 7”(800*480) screen displays clearly, even on a bright sunny day. In short, it is the second-best option available after Garmin Echomap UHD. 

3. Raymarine Element 7HV

Raymarine Element 7HV

The Raymarine Element series is top-rated among anglers. It comes with multiple exceptional features and offers quality with a long-lasting life. In other words, it is a compact, durable, and value-providing product. 

The Element 7HV features a bright 1500 nit LCD display, making it easily readable on sunny and cloudy days. It also comes with a Quad-Core processor. The HV-100 transducer is a beast. It allows anglers to see clear and high-quality images. Even more, it has a high coverage area capability. 

Raymarine Element 7HV features multiple mapping options. It provides HotSpot, Navionics, and C-map options that make it a suitable choice for various environments. The Raymarine RealBathy feature allows anglers to create custom contour maps of their favorite spots.  

Best Fish Finder Brands

It’s always a good tactic to buy products from well-known brands. We brought to you a few details about famous brands and the answer to “How does a Fish Finder Work” because it reduces the chances of fraud. All the famous brands have a long journey of satisfying customers and making profitable relationships with them. They won’t let you hate their products. That’s why it’s always a good tactic to buy branded Fish Finders. Here’s a list of the best Fish Finder Brands,

Best Fish Finder Brands


Lowrance is one of the market leaders in marine electronics. This company holds the honor of inventing the first consumer sonar device, the Little Green Box, in 1957. Since then, Lowrance has tried its very best to facilitate its consumer in new ways. They have developed many products that came in handy for anglers and helped them catch more fish. 

This company has more than 60 years of experience, and they are still providing the best fishing equipment in the market. Their CHIRP Sonar offers the best underwater imaging, both downwards and to the sides. Since introducing the first High Definition System Multifunction Display, Lowrance launched several new products and features that changed the fishing equipment market for good. The market leaders are still motivated to provide more value to the customers by inventing highly advanced products. 


Like many top US companies, Humminbird was started in a Garage back in 1971. Fishing electronic manufacturers tried their best to build new products to gain people’s trust. Their Journey may not have the best beginning, but things went very well for them after a few year’s struggle. 

The company’s first significant hit was a water-proof depth sounder, the Humminbird Super Sixty. It is still one of the best-selling fish finders ever produced. Since then, there’s been no stopping Humminbird. They continued to surprise us all and provided the most value-for-money products. The Humminbird is one of the best fishing equipment companies. Anglers from all around the world trust their products, and the enterprise continues to provide quality. 


Garmin is another well-known American company that engineers many types of products. They highly believe in providing good quality to their customers. Their marine electronic products are second to none. The company successfully made its name in the market leaders and striving for more. 

Garmin started its journey by selling a radio for $2500. In 1991, the US Army became their first major customer. The rest of the story is history. They started making millions in profit. Unlike most new companies, Garmin stuck to its goal and continued providing beautiful products. They focused on satisfying customers, and they achieved it. At the present time, they are providing value to their customers all around the world. 


Raymarine is another world leader in marine electronics for light commercial marine markets and recreational boating. Their products are designed to deliver the best in visual navigation information. They launched their first depth sounder in 1923. In 1975, they won the British Design Award for the first Autohelm tillerpilot. 

From there on now, they have surprised their competitors by providing highly advanced marine electronics. Their products are famous for their ease of use, rugged design, reliability, and durability. Moreover, they are constantly developing the best sensors and intelligent navigation systems. They are becoming angler’s source of happiness from all around the globe. 

Final Verdict

How does a fish finder work? That’s one of the most famous questions in the fishing world. Many anglers are curious to find the answer. In this article, we briefly stated the three types of fish finders and their working processes. Even more, we also listed three of the world’s best and value-for-money fish finders. Our team always thinks about our readers, and we will continue to search for answers to your favorite questions. If you have any, please feel free to tell us in the comments. Best of Luck!