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How To Read A Fishfinder

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How To Read A Fish FinderSo you want to learn how to read a fish finder? Don’t worry, you have come to the right place.

Fishfinders are extremely useful angler devices. They may seem complicated to read but the reality is, it’s easy.

And when you understand your graph you become a better angler instantly.

Like anything else, the more you use it and practice the easier it becomes. Fishfinders is a great way to find a very specific type of species underwater.

Not only is it a great tool to find fish. It will also help you to locate where your bait is in relation to the fish.

Most of the fish finders today use sonar technology to create digital images of the sea. This sonar technology produces sound waves which bounce off of objects and fish.

The image it produces helps you to locate fish. However, it doesn’t create an extremely accurate visual of the water below you.

But, understanding how it works and knows how to read it will make your fishing adventures much more pleasurable.

Here is a list of budget-friendly fishfinders

Aside from showing you how to read a fish finder you may also want to get your hands on some.

We have searched the internet with the intent to find you some of the best fish finders with a friendly budget.

Here is a list in no particular order (click on the image to see the review):

Raymarine E70294-US Dragonfly Fish FinderRaymarine E70294-US Dragonfly-4 Pro Sonar/GPS with US C-Map EssentialsYESYESCheck Price⭐⭐⭐⭐
Garmin Striker 4 fish finderGarmin Striker 4 with Transducer, 3.5″ GPS Fishfinder with CHIRP Traditional TransducerYESYESCheck Price⭐⭐⭐⭐⭐
Lowrance Elite-5 Ti FishfinderLowrance Elite-5 Ti 000-12421-001 Fishfinder Chartplotter with Downscan XdcrYESYESCheck Price⭐⭐⭐
Garmin echoMAP fish finderGarmin echoMAP CHIRP 54cv with transducerYESYESCheck Price⭐⭐⭐⭐⭐
Humminbird Fish FinderHumminbird 410210-1 Helix 5 Chirp GPS G2 Fish FinderYESYESCheck Price⭐⭐⭐⭐

Now, let’s continue on how to read a fish finder. Below are key features you should pay attention to.

Fishfinder View

You know, for years as anglers we basically had 2D sonar. Basically, it shoots a sonar beam directly below the boat.

The tough part about that is you only get a tiny amount of bottom coverage.

So around a third of your depth. What that means is, if you are in 30 feet of water, you’ll only be able to see roughly a 10-foot diameter circle.

But with the technology of today, we have more inexpensive higher quality imaging which not only allows a scan of the bottom but of the sides as well.

The images it produces are almost 3d like and have a depth of field to them.

A useful tip when using your fish finder is to use a split screen view of both 2d conventional sonar and down imaging to help you identify what you are looking at specifically.

The beauty about this is you get to see both sides. Sonar will give you a basic detail but the down imaging will give you more detail. So by looking at them side by side will help you distinguish of what is actually down there.

Reading A Fish Finder Screen

Here are some key factors to take into consideration when reading a fish finder screen.

Depth, Temperature, and Speed Sensors

how to read a depth finder – A lot of fish finders nowadays come to equip with a depth sensor. This allows you to tell exactly how deep the water below you is.

Why is this important? Knowing the depth of water will tell you more about the environment and what fish you can expect.

A lot of fish finders default settings in the depth settings will be set to meters. Most fish finders will allow you to change the reading to feet if that is what you prefer.

Another thing to take into consideration is the temperature. The temperature reading is normally located below the depth reading. Again, this is useful to know what type of fish may be in the area.

Since each specific species of fish prefer different depths and temperature. Utilizing just these 2 simple features will give you a better understanding of observing the different environments and types of fish around the area.

Let’s not forget about the speed sensor. The speed sensor, of course, will tell you how fast you are moving.

Why is this useful? It is a like a speedometer but for your boat. If you’re trolling to fast you’ll be able to tell instantly just by taking a glimpse on your screen.

Color and Echo Return Strength

Some fish finders come in color while other fish finders will only support grayscale (black and white). It all depends on your model.

The echo return strength will display a darker or stronger color based on the objects below.

When looking at the color and echo return it is good to note that the bottom of the water will be represented in either a thick, bold or thin light line. If the line is light then it means that the ground below is a softer material.

A thicker bold line means that the material on the bottom of the water is a lot harder and less porous.

This again, well tell you more about the environment for the fish. Never overlook these details.

Data Display

One thing to take notice when reading the data display on the fishfinder is that the results will display from right to left.

Basically, the most recent results will be shown on the far right of the fishfinder display. The oldest results will be on the left.

However, if you are moving your fishfinder will show you what is displayed directly below you at the right portion of the screen.

So a tip is to start off slow, find a speed that works for you and tries to get used to that.

Also, most fish finders will have a custom zoom settings in case you need to zoom in to get a better bigger picture.

Reading The Fish-ID

So, now you understand depth, temp, speed, color and echo. Now you need to understand what objects and fish may look like in your fish finder.

Nowadays, fish finders have Fish-ID technology which will convert the raw data into a more simplistic and user-friendly interface.

Basically, it will display fish icons where the fish are and often times it will display them depending on the size of the fish.

Some higher end fish finders will even display rocks, plants, and schools of fish.

However, Fish-ID isn’t always accurate. Sometimes it will display plants as a school of fish or even display rocks as plants.

So don’t expect miracles. Instead, take it as a guide and try your best to understand the type of fishing environment and what type of fish species you are looking for.

This is why understanding temperature and depth can take you a long way when using a fish finder.

Fish Finder Reviews

So now that you have a basic understanding on reading a fish finder.

Now it’s time to take a look at some of the best cheap fish finders and a small review to help you make a decision on your next purchase.

Raymarine E70294-US Dragonfly-4 Pro Sonar/GPS with US C-Map Essentials

Raymarine E70294-US Dragonfly Fish Finder

Optically bonded for sharp color, wide viewing angles and no internal fogging

Includes US lakes, rivers and coastal maps.

Includes transom mount CHIRP transducer with temperature sensor.

MicroSD memory card reader for saving sonar screenshots.

Dual-channel sonar – wide-spectrum CHIRP DownVision sonar for photo-like images and a second CHIRP conventional sonar channel for targeting fish.

4.3″ All-weather, high-definition LED backlit display.

Stream live sonar data to your smartphone with Raymarine’s Wi-Fish mobile app.

With the Wi-Fish you can rewind, save and share the day’s catch with friends on your favorite social networks.

Garmin Striker 4 with Transducer, 3.5″ GPS Fishfinder with CHIRP Traditional Transducer
Garmin Striker 4 fish finder

CLEARVÜ SCANNING SONAR – Shows you more of what is in the water around your boat.

This high-frequency sonar gives near-photographic images with detailed representations of objects, structure, and fish.

THE POWER OF SIMPLE – Offers a keyed interface with dedicated buttons.

The device is easy to use and easy to install.

Available in 3.5-, 5- and 7-inch display sizes.

Water rating IPX7

WAYPOINT MAP – Use the waypoint map to easily view, mark and navigate to locations such as brush piles, stumps, and docks.

Maximum depth-1,600 feet freshwater, 750 feet saltwater.

Current draw at 12V: 0.23A

CHIRP SONAR – CHIRP sends a continuous sweep of frequencies which provides a wider range of information.

CHIRP sonar is able to create crisper fish arches with better target separation.

BUILT-IN FLASHER – View your sonar data in the classic flasher format; ideal for ice fishing or vertical jigging.

Lowrance Elite-5 Ti 000-12421-001 Fishfinder Chartplotter with Downscan Xdcr

Lowrance Elite-5 Ti Fishfinder

Fish finder chartplotter combo.

Built-in GPS antenna for accurate positioning.

CHIRP Sonar and Downscan Imaging for a detailed view beneath the surface

TrackBack lets you review recorded sonar history.

Advanced Signal Processing (ASP) reduces the need for manual adjustments.

High-resolution 5 inch led-backlit color display; easy-to-use touchscreen.

CHIRP sonar. structure scan. downs can Imaging.

trackback features allow users to scroll back through sonar history to review structure or fish targets & mark the location with a waypoint internal GPS antenna.

Garmin echoMAP CHIRP 54cv with a transducer

Garmin echoMAP fish finder

Following in the success of the echoMAP CHIRP combo series.

Garmin is proud to announce the new echoMAP CHIRP combos with ClearVü scanning sonar technology.

The cv series offers built-in CHIRP traditional sonar and CHIRP ClearVü.

The sv series gives you built-in CHIRP traditional sonar, CHIRP ClearVü, and CHIRP SideVü capabilities.

Each display size for the echoMAP combos is offered with either U.S. BlueChart g2 charts, U.S. LakeVü HD maps, Canada LakeVü HD maps or a worldwide basemap.

New Garmin Quickdraw Contours software feature lets you create your own maps, with up to 1-foot contour lines, on any body of water.

Humminbird 410210-1 Helix 5 Chirp GPS G2 Fish Finder

Humminbird Fish Finder

At Hummingbird, innovation is the core of everything we do.

The new HELIX Series is no exception-delivering our full array of technologies, including the intuitive REFLEX interface, precise Broadband CHIRP, incredible Imaging SONAR and the mapmaking power of Auto Chart Live.

Fueled by DNA that is unmistakably Hummingbird, the HELIX Series also features a jaw-dropping industrial design.

From top to bottom, it’s plain to see that finding fish runs in this family. HELIX 5 CHIRP GPS G2 | HELIX 5 Series | 410210-1 The HELIX 5 CHIRP GPS G2 with our new user interface and operating system, features a brilliant 800H x 480V, 5″ 256 color display with backlight.

CHIRP Dual Beam PLUS sonar with 4000 watts PTP power output, Precision Internal GPS Chart plotting with built-in Anima cartography with a micro SD card slot for optional maps or for saving waypoints.

Maximize your angling experience with the Hummingbird HELIX 5 CHIRP GPS G2 fishfinder system.

How to read a humminbird fish finder

power up your hummingbird fish finder.

Have a look at the on-screen digital readings that appear. These may be depth, water temperature level, and boat speed readings, depending on the type of fish finder you have. Note that these readings are based on the transducer region that sends finder signals to the fish finder from the water.

When the bottom of the screen is studied, precisely the line that crosses it. A dense, dark line reflects a tough bottom, while the bottom is soft with a thin light line.

Look over the line that the bottom represents. The hard structure, submerged wood, rocks, or water vegetation are likely to be lines or other objects that reach up from the bottom. The density of the wood, rocks, or greenery and other objects is indicated by abundant lines or items in near proximity to each other.

The icons on some models depict fish. Note where these objects are in the water column, but bear in mind that the distinction between fish and other objects that may be in the water can not be deciphered by many fish locators.

It is very difficult to identify the fish size shown on the sonar because you can adjust the size with changes in sensitivity level or range of depth. On a twenty-foot depth sequence, fish appear larger than a hundred feet.

The color of the fish arch is used to describe the size of the fish. For example, if you have yellow, red and blue color palettes, the larger the fish, the more yellow you see. Likewise, the density of the fish arch describes its height. But the length of the fish arch is just how long the fish is under the transducer.

Humminbird Fish Finder Side Imaging

The side-imaging beam casts two thin beams. One on each side of the boat, in a 180-degree beam under the boat.

This projection covers a path up to 240 feet on either side of your boat from left to right.

You will be able to see the 450 feet sight of the water you will be fishing, which will in turn benefit you in your fishing endeavors.

When you look down at your boat from above you can clearly see the objects near the boat and their positions in relation to your boat.

In addition to that, most of the Humminbird fish finders which have Side Imaging has the feature of Dual-beam Sonar as well.

Thus, the sonar system works in water up to 1500 feet deep. Side sonar works only in water up to 200 feet deep.

If you want to go beyond that particular depth you will have to work with the switch fire mode.

Humminbird Down Imaging

The Down Imaging mode of Humminbird will allow you to see the surface under your boat. Similarly, it will help you determine what is going on under your ships. Similarly, the pictures at the bottom of Imagining are the development of ultra-thin slices of high-frequency sound waves.

In addition, on your computer, the objects that will be cut by a solar beam will appear, giving you a clear view of the shapes. You will be able to discover from this what the object really is. But the exact location of the object or on which side of the boat the object is will not be known to you.

In reality, the Baitfish appears as a cloud on the screen, just like in the side imagining mode, in the down imaging mode, and the biggest fish appears as a spindle-shape entity.

In calculating the depth length, down imaging is also helpful. It will help you to determine how deep each ditch is and the length of the mound that passes under your boat. Imagining Down will help you understand where you need to cast a high concentration of vegetation into water. In addition, you will be able to locate your target object through your display screen using the aid of down imagining.

Understanding Underwater Structure

You can read the underwater structure, which will help you mark the fish, by recognizing the sonar and identifying the screen display. The depth finder on your Humminbird Fish Finder’s transducer will help you understand the depth of the water underneath your boat. This will help you predict the kind of fish in a specific sea or river water.

In the top left corner of the display screen, the depth finder feature has its location. The function of the depth finder will help you display the water temperature. In addition, it will allow you to consider the sort of fish that you will be catching.

Video Demonstration On Reading A Fish Finder

If you’re still having trouble understanding and learning how to read a fish finder then check out these helpful videos below.

video by wired2fish:

video by fish the moment:

Frequently Asked Questions

What does fish look like on a fish finder?

While fish can look the same with a 2D sonar, on side imagery, fish appear smaller because it features a down beam that comes as a narrow water column slice. So you’re probably seeing something like a crappie that looks like a circle, or a tiny oval.

How does a fish finder work?

Pulses of sound waves are sent down through the water by a sonar system. They are mirrored back to the surface as these pulses strike items such as fish, vegetation or the bottom. The sonar instrument calculates how long it takes to move down the sound wave, strike an object, and then bounce back up.

What should I look for when buying a fish finder?

Starting fishermen may be confused by all the features and choices when selecting a new fish finder: power wattage, number of pixels, with or without a transducer, display screen size, and the list goes on and on. But you should not go without one feature, and that is GPS.

Do fish finders work in shallow water?

You can look for a fish finder that has a sonar frequency of at least 200kHz or higher for fishing in shallow water. Higher frequency contributes to higher and better resolution, enabling you to more accurately position yourself (or your boat) over the fish.

Can fish hear fish finders?

Fish finders don’t produce enough noise to scare fish, or the frequency is too low to hear them. Most transducers produce ultrasonic waves, which as a result cannot be heard by fishes, thus making them less detectable.


There you have it. How to read a fish finder. Always remember that the fish-id isn’t always accurate and knowing your depth, temp and enviorment will help you determine the fish species in your area.

Now that you understand and know How To Read A Fish Finder. It’s time to purchase one if you haven’t already and start finding fish!

Be sure to follow us on instagram @uluacom also if you enjoyed this write up you may also be interested in What Size Test Line for Bass Fishing or How To Tie A Fish Hook.

Also our reviews are based on our opinion and based on information found online by other customers. Always do your own due dillengence before making a buying decision. Till next time! Aloha! and have a great day!

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