Facts You Need To Know About Reading A Fish Finder Screen


Fish finders are considered to be one of the most useful fishing tools available on the market today. This handy device has made fishing much easier for fishing enthusiasts. If you know the basics of catching a fish, you will find it easier to improve your skills with the tool.

However, after you have selected a fish finder to use, there comes the complicated process of learning how to use it. Although it has been advised that you have to keep it basic when distinguishing the details provided by the tool, there are more things that you have to learn.

Truth to be told, most first-time users of fish finders do not even understand the details displayed on the screen of their tool. You should not be ashamed if you are in the same situation. There are even experienced fishermen who are honest enough to say that they still don’t fully grasp the purpose of the tool.

Facts You Need to Know About Reading a Fish Finder Screen

To help you with the task of finding out what the graph of a fish finder entails, you should learn facts from experts. Given below are a few details that will help you with comprehending the figures, graphs, and calculation shown by a fish finder:

Learn How the Tool Works First. In order to understand the details shown by the fish finder you bought, you must first understand how it works. Primarily, the transducer of a fish finder emits sonar waves. The bottom part of the equipment is the transducer.

The sonar waves, when transferred, will bounce around and return. From then on, the transducer will evaluate the rate, distance, and speed. This is when raw data conversion will follow. The visual data shown on the screen display of a fish finder comes from the information returned by the sonar waves.

More often than not, you will see arches and colored lines on the display. You will notice that the lines are set at various depths. This shows the depth, and it is helpful information that will give you information where fish can be found.

The most important thing you must learn about a fish finder is its depth detection. This is responsible for telling you how deep the water is. This is imperative so you will also be able to identify the fish species under your vessel. Depth can be displayed in either feet or meters.

Apart from the depth finder, the tool also provides information about the water temperature. This is also essential in finding certain types of fish. Take note that there are aquatic animals that prefer a cool environment than warm water, and vice-versa.

If you combine accurate temperature and depth information, it will be easier to look for fish. Fishing conditions can also be improved if you are able to observe various environments that aquatic animals prefer.

Lastly, another fish finder information that you will find useful is the speed sensor. This is responsible for giving you an idea of how fast your boat is moving. For most professional fishermen, this is important.

Understand Two-Dimensional Sonar Interpretation. You will often encounter fish finders marketed for beginners that come with 2D sonar technology. This is due to the fact this is the basic means of reading the water column.

Primarily, the cone’s angle is based on the frequency used by the equipment. For instance, a fish finder that uses 200 kHz beam frequency will provide a wider coverage area.

You should keep in mind that the tool is continually listening and pinging. Whenever the sonar waves return, data will be processed continuously. If your equipment is using 2D sonar technology, you will find older moves interpreted on the left side of the screen, whereas the new details are on the right.

In case a larger fish moves through the cone, you will see an arch on the fish finder’s screen.  Whenever you paddle up a slope under the water, you will notice that the screen’s depth will also change.

If you see blobs, you are likely encountering brush or a school of fish. This is due to the fact that the transducer detects everything that is found in the cone. If you see clouds, arches, or round marks, you can consider them as fish. As for larger species, you will see solid hues.

As for the hard bottom, you will often see it as bright yellow color with a blue shade under it. Once you pass a mucky bottom, the said colors will change to orange.

Interpret Down Imaging Sonar Interpretation. You should know that with this sonar technology, there may be differences when it comes to the images that you will see. First, you must know that fish in Down Imaging Sonar is smaller than what you will see in 2D sonar.

Schools of bass, on the other hand, will likely be quite larger and spread out under the water. Circles or small ovals will represent the crapper. Lastly, a spotted bass may appear to stack up on one another.

On a Down Scan sonar, it is very easy to distinguish the hard bottom from other elements under the water. It will appear with a considerably brighter hue than the soft bottom. Color changes to separate the areas where rock, gravel, and sand can be found.

Determine the Difference of Structure Scan Imaging. You can consider structure scan imaging as the side imaging sonar. From the name itself, it will be more difficult to find fish on the display since the beams are directed to the side.

Most of the time, the imaging results give off brighter returns when fish is present. You will only see sonar shadow when the species are off the bottom. To find out the species’ suspension, you simply have to check the distance between the fish and shadow.

The aquatic animals that are holding tight on the soft bottom will have brighter returns. Alternatively, fish that are on the hard bottom will be hard to spot and likely blend in.


By considering the facts listed above, you will be able to read your fish finder’s results more effectively. Do keep in mind that there may be discrepancies in the readings depending on the product you are using.

There are cases that even color palettes differ from one fish finder model to another. Before you use the equipment, be certain to read the instructions carefully.

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