Featured image of an angler catching a rainbow trout in a fish finder buyers guide.

The Ultimate Fish Finder Buyers Guide For The Serious Angler

​Quick Tips On Selecting The Best Fish Finder

  1. Image of two people fishing on a lakeDon't out cheap yourself. Make sure you buy the type of fish finder that will work for you in the long run. Many anglers who have not taken the time to read a fish finder buyers guide regret getting too small of a display or one that is not very powerful. They limited themselves in their fishing experience to save a few bucks.
  2. Consider units that can be upgraded. If money is an issue, then pay attention whether or not the unit you are considering can be upgraded. If so, then maybe you can buy an upgradeable unit now and upgrade it next year.
  3. Buy what you need. As we all know, money doesn't grow on trees. As much as the top notch features are tempting, if you are not going to use them, then you have spent more than you need. Ask yourself what type of fishing will you do? If you are sticking to shallow lakes or streams, then maybe you don't need the most powerful fish finder out there.

Understanding The Functions Of A Fish Finder

​There are two main components of a fish finder. They are the display unit and the transducer. The transducer is the component that produces the sonar that is read by the display unit. Here are some important aspects of both of these units.

The Display Unit

Display units come in all types of sizes and shapes. Some are small enough to mount on your rod while others really need to be mounted on the dash of your fishing boat.

The display unit is the part of the system that controls all the aspects of the fish finder system. You set the sensitivity and type of signal produced from the transponder. You don't want to skimp on the display unit. You can have the most sensitive sonar in the world but if it is displayed on a lousy display it won't help you find fish.


Resolution is the amount of pixels that are used in displaying the image. A pixel is a dot of image information. If you have 800 pixels of resolution then it takes 800 dots to go from the top to the bottom of the image in a straigh line. So 800x800 resolution is 800 dots across by 800 dots down. The larger the display resolution the more defined the screen image is going to be. Do not go below 240 pixels top to bottom. The image will be too fuzzy to be of any use to you and even then it is pretty fuzzy.

Screen Size

​Bigger does not always make better. Smaller screen sizes are better for small boats, kayaks, and rubber flotation devices and larger ones are better for boats with cockpits. However smaller size fish finders do have their drawbacks especially with multi-screen mode or when being viewed from a distance.

Multi-Screen Functionality​

​Some fish finders come with the option to view multiple screens at the same time. Some units will show you different views of the bottom and others will show you a map and your sonar at the same time. This functionality works best on units with larger screens.


​Modern fish finders have moved away from black and white screens. Color allows you to be able to define the image better. In this case, the more bits of color, the more your image will be defined. They can range from 16 bit color up to millions of shades of color and beyond.

​Additional Features

The best fish finders will not just show you the depth of the bottom and what is below. They will show you water temperature, speed you are traveling, GPS position and more. Some even come with alarms to notify you when it finds fish!

The Transducer

Picture of a fish finder mounted on the transcomThe transducer is the unit that produces the sonar signal. It sends a ping into the water and then receives the echo back and translates that into data that the display unit can understand. Most transducers are mounted on the outside of the boat although there are a few that will operate through the boat's hull.

Here are some key features of transducers.


​The frequency is the number of times the transducer emits a sound wave per second. These are measured in KiloHertz. Most transducers will come with either 50, 83, 192 or 200 kHz frequencies. Higher frequencies, like 192 and 200 kHz work best in shallower water, while the low 50 kHz transducers work best for use in deep water. High frequency sonar however, uses more battery power.

Many fish finders have the ability to use more than one frequency at a time making the sonar results better.​ There are 4 major types of frequency types used in fish finders.

  1. Single Frequency. This is in all basic fish finders. It is best used in portable and shallow water situations.
  2. Dual Frequency. The transducer uses 2 set frequencies to gather it's sonar data. This gives you better clarity.
  3. Multiple Frequency. This is where you have more control over what frequencies are used with variable settings.
  4. Chirp Technology. (Compressed High Intensity Radar Pulse) This technology emits a variety of frequencies simultaneously giving you the most complete sonar image available today.


The transducer's power has a direct impact on your fish finder's clarity and depth. The power of the transducer is measured in watts. The higher the watts, the more powerful it is.

As a practical matter, the deeper you fish, the more power you want but if you are mainly a shallow water angler, then you can get away with a lower wattage transducer. As a rule of thumb, ​at 50 kHz, for every 100 watts of power, your finder/transducer can show readings up to 400 feet.

At 200 kHz, for every 100 watts of power, your finder/transducer can show readings up to 100 feet.Most mid-range finders available are dual-frequency, so you can see readings from both frequencies(usually 50/200 or 85/200) in a split screen fashion.

Cone Angle​

The cone angle is the dimensions of the beam as it is sent from your boat into the water. It looks like an upside down ice cream cone. The wider the degree of the cone angle, the larger of an area is scanned below you. A 50 degree cone angle will theoretically cover more area than a 15 degree cone angle. However you need to remember that the larger the cone angle the less sensitive your fish finder become at deeper depths.

Most units start at 15 - 20 degree cone angles. This is usually a good starting point for your fish finder.​ Higher quality units come with more than one cone so you can use one for down sonar and one for side sonar.

What To Do After Reading Our Fish Finder Buyers Guide

Ok, now that you have read our fish finder buyers guide and have a basic understanding of fish finders, check out our list of the most outstanding fish finders on the market today. Or you can do further research on fish finders with these informative articles.