How to Read a Fish Finder Screen

Are you planning to enjoy the day out on the water?

If so, Fishing is one of the most fun and interesting activity to spend your time with the family or friends. The fishes usually live in the places where they can get their prey, but it’s important for them to have eyes over the predators too.


If you find the water condition and in thorough of the fish habits, then you can identify the spot quickly. The fish finder makes your fishing experience easier and it gives the clear details whether it contains single or group of fishes beneath the water.

How Fish Finders Work

The fish finder uses sonar technology to capture the image of the underwater area and then it will display it on the screen. Most of the fish finder comes with the GPS receiver, transducer, Bluetooth, networking devices and many other accessories.


The main function of the transducer is to detect the things around the particular region and then it sends the collected information to the head unit. It contains piezoelectric elements for creating vibrations at certain frequencies and it converts the return signal into an electric signal.

GPS and Chartplotters

Some fish finders contain GPS capability for tracking the positions using the map. It allows you to note the exact point where it contains more fishes and then you can use the information for later reference. The built-in software works magically for displaying the images on the screen from the collected data.


The fish finders are available in different shapes and sizes. Get the device with the biggest screen if you want to see more information on the display. The average size is 3.5 inches and using the 9 inches screen you can view both sonar and chartplotter details at one time. It is important to choose the high-resolution fish finder for getting more clear and accurate images.


The networking features are now included in most of the fish finders and the device gets connected to the hub automatically. Some of them use Ethernet system like the Hummingbird and other uses NMEA2000 system for creating the connections to the units.

How to Read the Fish Finder Screen

It is necessary to understand the interpret data which is displayed on the monitor screen because each fish has its own necessities, food, temperature and depth etc.

Depth, Temperature, and Speed

The transducers fixed in the fish finder collects the data such as speed, temperature, distance and the rate of the returning waves. Then it converts the information into the visual data which is in the form of thick lines, arches and dots.

The line represents the different depths and the arch denotes the presence of large fishes. The depth finder gives details about the level of the water and this information will get displayed on the left side of the screen in feet or meters.  

The depth readings also show the water temperature and you can find the special type of fishes which lives in particular depth or temperature. The speed sensors are included in most of the fish finders for detecting the speed of your boat and make sure to pay attention to the features before getting the device for you.

Color and Echo

The fish finder displays the information in different colors and some produce in grayscale like black and white. The hardness of the objects is represented by the strong colors and it is mainly based upon the echo received by the device. The bottoms of the ocean, lake or river are denoted by the lines, if the below region is rocky surface it will be represented in a thick line.

Data Display Sequence

First, set the fish finder then move slowly around the place and you can get an idea how your monitor screen displays data. The most fish finder works better in slow speed and try to maintain the optimal speed while using the units.

You have to read the data from right to left because the most recent data will get displayed on the right side and the left side contains older information. Use the zoom in option when you want to focus the particular object.  

Reading Fish-ID

Now, you have to understand the objects to identify the fish and other objects that look like the fish. There is the option for converting the dots or arches into the different sizes of fish symbols using the fish ID technology. It also contains various icons for representing the school of fishes, plants and rock which is present beneath the water.

Bottom Line

Though the fish finder looks like a complicated device, you can understand it easily. You require just some time to learn about the details that get displayed on your fish finder monitor.

After clarifying your doubts, you need to check whether you can identify the fish and its location for the proper use.

Let’s know in comments if you are using any fish finders?

How to Use a Fish Finder to Catch More Fishes




How to Use a Fish Finder


Understanding the Display




Locating Fish and Mapping the Area




Adjust the Display





Bottom Line:



Happy Fishing!