How to Read a Fishfinder – What Every Fishers Should Know

As a fishing enthusiast, then you may have heard of fishfinder before. However, not every fishers know the technique on how to read a fishfinder. It is something you need to master and it may sound complicated at first, but keep in mind that after some time, this is going to be more than just an easy task. After all, fish finders are designed and made to be as easy to read and use as possible, so there are no unknown data!

how to read a fishfinder

The simplest explanation is to know that all fish finders use sonar in order to operate. Sonar means that they will send a signal to the depth of the water at all times and measure the returning signal. In other words, a sonar will measure the time and the signal strength that is sent and received.

That’s signal is then analyzed and displayed in real time in simple symbols. Those symbols will have to be read carefully and they will make a massive difference in determining is there a fish below the boat!

Reading the Fish Finders

First of all, there are a lot of different models available on the market and most of them display different symbols at any given moment. But we will generalize the matter and help you understand the symbols that can be related to any fish finder.

Finding Fishes

Obviously, the first and the most important fact to consider is to find fish below the boat. But, is there any fish?

Modern fish finders can display signals in two forms. The first form is more suitable for beginners. Basically, you will see fish icons on the screen. When detected, it will simply mean that there is fish below. These icons will vary in size and shape, meaning that the fish finder will automatically display the size of the fish beneath the boat.

Professionals use a different method. They use archers. For them, this method is more accurate and more appealing, but for beginners, it is more complicated. All you have to remember that instead of fish icons, you will see arches, which will vary in size, length, and width. This is the next factor we will have to explain.

Understanding the Size of the Fish

Let’s take into consideration that you are using fish arches to find fish. You already know that there is fish in the water, so you can start fishing. But, how big that fish is? That’s why you will have to pay close attention to the length and the width of the arches.

Length is caused by a fish that is stationary or moves slowly. It doesn’t have anything to do with the size of the fish. So, a small fish that is stationary will make a long arch. Just because you see a long arch, it doesn’t mean that you have discovered a blue whale. On the contrary, it may be a very small fish.

The size of the fish will be displayed accordingly in the width of the arc. As such, wider arches will suggest there is bigger fish below. Obviously, the width of the fish is a more important factor to consider.

If you are a beginner, switch to the fish icon and use it until you get an idea how fish finders operate.

Understanding the Underwater Structure

Now when you know all about the previous factors and symbols, you will have to understand that underwater structures have an important role. Here are a few facts you will have to remember first. Don’t forget that a fish finder will constantly scan the area beneath the boat and make adjustments to the display.

Humps and drop offs are very easy to spot on and we won’t waste your time here. Basically, they are presented as they look, so you can detect them within seconds.

Here we must mention a few, additional processes. The first one is to switch between wide and narrow signal scanning. This will simply give you a much better insight into what is beneath the boat and how it looks.

Now you will have to turn on the depth alarm. You will want to be alerted of the desired depth once you reach it.

Almost all fish finders come with a classic and day color setting. The classic one is definitely a better option for beginners. Basically, you get green vegetation displayed, which is simpler to understand. A day mode will display them in purples, which may be a bit unclear for some of you.

Understanding the Sea Bottom

Now you will want to see what type of surface is at the bottom. There is a simple way to do this. Orange is used to represent the hardest types of bottom. Brown is used for representing soft surfaces.

Hard sea bottom floors are always presented in one, single line. Softer ones are presented with dashes and green additions. More of them means a softer surface, which isn’t very consistent.

More advanced fish finders will have the ability to measure the thickness of the floor. You have the ability to adjust the sensitivity in percentages. Higher sensitivity should give you more accurate data. In this case scenario, we must recommend you to practice sometime. You will find it useful when you are located in a new position and you want to determine all the symbols you got from your new fish finder.


In the end, all we can say is that fish finders are relatively easy to use and comprehend. Yes, you will need some time to get used to them, if you are a beginner, but all of this is incredibly simple and easy. Now you will have to practice for some time, but once you are done, you won’t have any complications.

All of which we have mentioned here are simple and basic factors and symbols. If you are interested in more, you will need to analyze the advanced settings and features of your fish finder and to get the most out of it.

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