Fish Finder Buyer's Guide
See which fish finder technologies, features, and brands make the most sense for your style of fishing.
by Ben Team
There are three key challenges that confront anglers seeking to catch fish. You have to entice the fish to strike your bait or lure, and you must set the hook and play the fish properly to get him up on the boat. But before either of these things matter, you have to overcome the first – and often most difficult – challenge the sport presents: Locating the fish.
Extending an Angler's Senses
For the bulk of angling history, anglers had to rely on their powers of observation, experience and wits to find the fish. After all, fish are rarely visible from the surface, so you can’t see them the way hunters see their quarry or bird watchers spot new species.
But in the early portions of the 20th century, electronics manufacturers began developing and selling sonar units. This allowed anglers to “see” beneath the surface for the first time. Early models were only helpful for determining things like large-scale lake structures and water depths, but as time went on, the capabilities of these sonar units grew significantly.
A Stacked Deck of Features
Modern fish finders not only allow you to find things like river channels and determine the depth of the water in which you are fishing, but they can display remarkably detailed images. Many of the best fish finders display things as minute as baitfish, rocks and individual tree branches.
Many of the better units also provide a wealth of supplemental data and capabilities, such as GPS information and wireless connectivity, so that you can send the information from your fish finder to a tablet or smartphone.
But while modern fish finders have transformed angling, and most modern sportsmen and sportswomen consider them mandatory equipment, it can be quite difficult to sift through the available models and pick the best fish finder for your needs.
We’ll try to make this process easier by explaining the way fish finders work, analyzing the needs of different anglers and recommending the features you’ll want to seek when making your selection. We’ll also provide some basic information about the major manufacturers on the market and define some of the common terms used to describe these tools and the capabilities they possess.
Open Table of Contents
How Do Fish Finders Work?
Fish finders are essentially sonar units. They emit high-frequency sound waves into the water, which then bounce off any solid objects in their path. The sonar unit collects these returning waves and processes them via a small computer circuit. This data is then translated into a visual representation of the water below. As the fish finder unit moves across the surface over time, the visualization scrolls across, creating an ongoing two-dimensional picture of what's under the surface.
In a nutshell, this process involves calculating the time it takes a sound wave to hit something and bounce back to the transducer. This allows them to determine the distance (depth) between the transducer and the object. Additionally, other properties of the returned signal, such as signal strength, allow the computer to determine some of the characteristics of the object. For example, a sonar signal that bounces off a rock will differ from one reflected off a weed bed or fish.
Different fish finders emit signals of different frequencies, and some fish finders emit more signals per unit of time than others do. Additionally, the computers and displays used in different fish finders vary in terms of quality and performance.
Many fish finders work in conjunction with GPS data so that you can not only visualize what is happening beneath the surface but also determine your location in the water.
Until virtual reality comes to fish finders, your own interpretation is the most important component of your fish finder. To get the most from even a basic fish finder, take the time to picture how a single fish arch represents:
- time passing as the transducer moves over the fish
- distance from transducer to fish changing as time passes
- angle from transducer to fish changing as time passes
- strength of the returned sonar signal changing as time passes
Fish Finder Categories
There are several different types of fish finders available on the market. And while any fish finder can help you catch more fish, you’ll want to select the best type of fish finder for your situation and needs.
Conventional Fish Finders
Conventional fish finders typically perform one central function: They collect data about the world beneath the surface via sonar technology and then display this data on some type of screen in a way that is helpful to the angler. This helps you to learn more about the lake, river or ocean in which you are fishing, and it makes it easier to locate fish.
Conventional units can usually provide anglers with information about the water depth, water temperature, major structural features and objects in the water, including vegetation, shipwrecks, sunken trees and any fish that are present.
The amount of detail displayed varies significantly from one unit to the next. Entry-level fish finders generally present somewhat crude images, while high-end fish finders present photograph-like images that are rich in detail. Some of the best units enable you to spot things like individual tree branches or clumps of vegetation.
Conventional fish finders are usually designed to be mounted on your boat, kayak or canoe, although some enterprising anglers elect to attach them to docks or other structures.
Flashers are somewhat primitive sonar units, which typically display three key things about the water below: The bottom depth, the depth of your lure and the depth of any fish below you. While they don’t provide nearly as much information as most modern fish finders do, many anglers appreciate their simplicity.
Most flashers display their data via a circular graph that correlates to the depth of the water. Objects within the beam of the sonar signal appear as lines along the edge of the circle. The placement of the line indicates the depth of the object.
Flashers are most popular with ice anglers, although they are also very helpful for those who like to use vertical jigging techniques in deep water. Many modern fish finders include a flasher function, which gives you the best of both worlds.
Dedicated flashers are typically designed to be portable, so that ice anglers can carry them around the frozen surface, as they move from one hole to the next. Some manufacturers offer optional “portability kits,” consisting of a padded travel case and a few other items to make the flashers easy to use, carry and set up.
GPS-Fish Finder Combos
GPS-fish finder combos are essentially conventional fish finders, which also feature a GPS circuit. This allows these types of fish finders to provide anglers with information about the watery world beneath their boat, as well as information about their location.
GPS capabilities provide a ton of value for anglers. They allow you to mark (and later revisit) productive locations, they allow you to track your route through a lake or river, and they give you the chance to see a bird’s eye view of the waters, among other things. Most GPS-equipped fish finders also display your traveling speed.
Many GPS-equipped fish finders are also designed to work with plotting charts, which can provide even more information about your location and aid in navigation. While GPS capabilities were once a high-end feature only included in professional-caliber fish finders, most mid-level fish finders now offer GPS circuits.
Castable Fish Finders
Castable fish finders are small transducers that are designed to attach to the end of a fishing line. You can then cast the transducer out into the water where it will begin emitting sonar signals into the water below. These sonar signals bounce off various things in the water and are collected by the transducer, which then transmits the data to a hand-held display or smartphone.
Because they needn’t be attached to the hull of a boat, castable fish finders are most popular among shore anglers and those piloting kayaks, canoes and other small crafts. However, some anglers in traditional fishing boats like to keep one on hand, as they are useful for gathering data about difficult-to-reach pockets of water.
Because castable fish finders rarely come with a display unit, they are often very affordably priced.
Some castable fish finders' batteries can hold a charge of several hours for six months or more. You can toss one into your tackle box and keep it as a backup for your primary fish finder.
Fish Finder Users
Anglers approach fishing in a number of different ways. Some fish directly from the bank, while others fish from canoes, kayaks or float tubes. Still others prefer to fish from traditional boats.
As you’d expect, these different fishing approaches require anglers to use different types of fish finders and to use them in different ways. And while there are no hard-and-fast rules dictating the types of fish finders different types of anglers should use, there are clear trends regarding the capabilities and features different anglers require.
Offshore/Inshore Boat Anglers
Most fish finders are designed for use with conventional fishing boats, so anglers who fish from boats typically have the widest selection from which they can choose. While a range of products certainly give offshore and inshore anglers great flexibility, it can make it difficult to sort through the numerous models.
Most fish finders are designed to work in either freshwater or saltwater, although some are clearly better suited for inshore anglers than offshore anglers, and vice versa. In general, the farther you fish from shore, the more you should prioritize fish finder power (which improves the depth range of the unit), GPS functionality and chart plotting capabilities.
Freshwater and inshore anglers, by contrast, are best served by prioritizing things like advanced imaging technologies and display quality. However, GPS capabilities and power are still important considerations.
Note that sonar signals travel further in freshwater than in saltwater, and most manufacturers provide different depth ratings for the different types of water.
Some of the most important things offshore and inshore anglers should seek in a fish finder include:
- Deepwater capabilities so that you can find fish in several hundred feet of water.
- GPS capabilities to pinpoint your location and allow you to mark waypoints.
- Chart-plotting capabilities to aid in navigation.
- Bluetooth or WIFI connectivity so that you can monitor your fish finder from anywhere on the boat.
- Radar functionality, which will allow you to see above-the-surface obstacles from afar.
Anglers who fish from kayaks and canoes can often utilize the same fish finders as their conventional-boat-piloting counterparts can, but it is important that they use models that are well-suited for small crafts and small waters. However, kayakers who venture out into the sea will need to consider the same things inshore and offshore anglers do when making their choice in a kayak fish finder.
Some of the most important things kayak- and canoe-piloting anglers should seek in a fish finder include:
- Ease of installation and removal to facilitate use and storage of the canoe or kayak.
- Side-imaging capabilities so that you can explore the water more quickly.
- GPS functionality so that you can determine your location and traveling speed.
- Excellent screen quality to help you see the display in bright sunlight.
- Map-making functionality for those who fish small rivers and ponds.
Anglers who like to fish from dry ground have the fewest available options in the fish finder market. In fact, shore-bound anglers didn’t have any fish finder options aside from flashers for many years. However, a number of manufacturers have recently begun producing fish finders specifically designed for the unique needs of bank anglers.
Most bank anglers choose to use castable fish finders so that they can collect data on a variety of different locations. However, some anglers who like to fish from the shore prefer to set up a traditional fish finder, by attaching it to a dock or similar structure.
If you like, you could purchase a top-of-the-line fish finder with a multi-thousand dollar price tag and use it to fish from your local pier, but most of the unit’s advanced features wouldn’t be applicable to your circumstances. Accordingly, most bank anglers choose fish finders at very reasonable price points.
- Some of the most important things shore anglers should seek in a fish finder include:
- Wireless connectivity to allow you to view the information collected by the fish finder on your phone.
- Small size and to allow you to cast the fish finder as far as possible.
- Rugged housing to ensure the fish finder will withstand the wear and tear of repeated casts.
- Side-imaging capabilities to allow you to view more water (if you plan to mount a traditional fish finder to a dock).
- Map-making functionality if you prefer to fish small waters.
Key Fish Finder Terminology
Many anglers have difficulty wading through the copious amounts of jargon used to describe and distinguish between various fish finders. This can make it difficult to compare different models, and it often clouds the decision-making process.
Try to avoid these problems by familiarizing yourself with some of the most common fish finder terms listed below. Note that some of these terms are not specifically related to fish finders, but they are explained in the context of fish finding units.
Click below for the full terminology list.
See Full Terminology List
Chart plotting functionality refers to the ability of a GPS-equipped fish finder to integrate the information from the GPS with a digital plotting chart. Some fish finders with these types of capabilities are called chartplotters. Chart-plotting-capable fish finders often provide a wealth of navigational aids, and they are especially prized by offshore anglers.
A type of sonar technology that is integrated into many modern fish finders. In contrast to traditional sonar units, which emit a pulse containing one, two or three signals of different frequencies, units with CHIRP technology emit a pulse that sweeps across a wide range of frequencies. This provides more information about objects in the water, which enable the fish finder to produce a more detailed image.
Garmin’s term for proprietary down-imaging scanning sonar technology.
Lowrance’s term for their proprietary down-imaging scanning technology.
Garmin’s former term for their proprietary down-imaging scanning sonar technology. They now use the term ClearVu when referring to their down-imaging sonar.
Raymarine’s term for their proprietary down-imaging scanning technology.
(Hybrid Dual Imaging)
A feature of some Lowrance fish finders, which combines their Broadband Sounder™ technology with their DownScan Imaging technology to provide a very detailed image.
This refers to the frequency of the signal transmitted by the fish finder’s transducer. Typically, lower-frequency pulses penetrate further into the water column and allow you to image deeper objects, but higher-frequency pulses provide greater detail.
A technology allowing you to view several different types of data on the screen simultaneously. For example, you may want to monitor your boat’s position with the GPS mode on one window and watch the scanning sonar images on another. Some fish finders allow you to view four or more windows at the same time.
Scanning sonar technologies are another relatively new innovation, which provides more detail and better clarity than traditional sonar technology can. Whereas traditional sonars emit a cone-shaped beam of pulses into the water, scanning sonar units emit pulses in a series of “slices” – somewhat like a CAT scan machine does. Scanning sonar technologies are typically available in down- and side-imaging versions.
Lowrance’s term for their proprietary side-imaging scanning technology.
Garmin’s term for their proprietary side-imaging scanning sonar technology.
An alternative term for a fish finder or flasher.
A transducer mounting style, which requires you to thread the transducer through the hull of the boat to mount it. This is generally the most difficult and elaborate type of transducer-mounting style, but it typically yields the best results.
The transducer on a fish finder is the component that transmits and receives the sonar signal. Most transducers attach to the bottom of your boat, but the transducer for a castable fish finders is the floating component that you cast.
A transducer that is designed to be mounted to the underside of your boat – typically via an angled bracket. This is one of the easier ways to mount a transducer, but it is important to use care when piloting your craft in shallow water, so you do not damage the transducer.
trolling motor mount
A feature of some fish finders allowing them to attach to a boat’s trolling motor. This is typically one of the easier mounting styles available, and they are frequently preferred by those piloting kayaks and canoes equipped with trolling motors.
A rating that indicates the power of a sonar unit. It is always preferable to have the highest-powered sonar possible, but higher-powered fish finders cost much more than lower-powered units do. Typically, anglers working farm ponds and small rivers need only 200 Watts of power, while deep sea anglers will want at least 1,000 Watts of power.
Marked locations – such as an important fishing location or your home dock – displayed on a GPS-equipped fish finder. By marking a waypoint, you’ll be able to find the spot again in the future quite easily. Waypoints can be displayed on a dedicated waypoint map, or they may appear as overlays on traditional maps and charts.
Features to Consider
Whether you fish from the shore, a kayak or a conventional fishing boat, you’ll want to get the best fish finder available at a given price point. This means you’ll have to compare the various features offered by different fish finders to arrive at the best choice.
The following features are some of the most important to seek when making your choice. You needn’t necessarily purchase a fish finder that provides all of the listed features, but you’ll likely want the most you can get for your dollar.
GPS-equipped fish finders provide you with information about your location, as well as the objects under or beside your boat. This type of information is invaluable for finding productive fishing locations, navigating the water and scouting new waters. Most fish finders now come equipped with GPS, but some of the more economical, entry-level models and castable fish finders do not.
High-Quality Display Screen
It doesn’t matter how much data a fish finder collects if it can’t display this data in an easy-to-see manner. Accordingly, you’ll always want to select a fish finder that has the best display screen possible. Generally, this means seeking a unit that has a high resolution and produces color images.
Adequate Screen Size
While it is definitely important to select a screen with a high resolution and full-color images, it is just as important to select a fish finder with the largest screen possible. This not only makes it easier to view images when you are close to the unit, but it can make it possible to see the images while you are fishing at the other end of your boat.
Most of the best fish finders allow you to customize the way the transducer collects information, which is useful for fine-tuning the unit, and the way this information is displayed. For example, some fish finders allow you to change the display colors, which can be helpful for maximizing the contrast and visibility displayed in poor weather or dim lighting, and most will allow you to select different types of data to display.
Fish finders vary in both the way they are designed to be mounted to your boat and the degree of difficulty they present during the process. It is usually preferable to select a unit that is easy to install, but it is particularly important for anglers who must mount and remove the fish finder repeatedly.
For example, anglers who rent boats for fishing will want an easy-to-mount fish finder, as will those who fish from kayaks and canoes, as these types of boats are often stored between fishing trips.
If you plan on vertically jigging in deep water or spending a lot of time ice fishing, you’ll definitely want a fish finder that includes a flasher function. The flasher function will eliminate any unnecessary information and allow you to concentrate on the fish and your lure.
Water Temperature Probe
Water temperature is a very important factor that influences fish behavior, so it is almost always helpful to select a fish finder that has a temperature probe inside the transducer.
Custom Map-Making Functionality
Anglers who fish large waters can usually find navigational charts that detail the lake or river in which they are fishing. However, those who fish in small farm ponds, rivers and creeks can rarely find maps or charts that provide the kind of detail desired. Fortunately, many fish finders provide map-making capabilities, which enable anglers to make their own custom maps on the fly.
You’ll often find it helpful to take some of the information contained in your fish finder and transfer it to your home computer or a friend’s fish finder. Accordingly, many manufacturers make fish finders that utilize SD cards, which can be used to transport the data you collect.
Preloaded Maps and Charts
Some fish finders with GPS and chart plotting capabilities come with preloaded maps or charts. This prevents you from having to purchase separate maps for your device, and because some map packages are expensive, it helps to improve the relative value of fish finders that come with them.
Wireless Device Compatibility
Many modern fish finders are capable of connecting to other devices, such as your smartphone or tablet. This allows you to control your fish finder and view the images produced no matter where you are on the boat. It also allows you to transfer data (such as waypoints, navigation routes and custom maps) to your other digital devices. Most modern fish finders are compatible with both Android- and iOS-based devices, but it is still wise to verify that the one you are purchasing is compatible with your devices before you make your purchase.
Kids love to watch the action on a fish finder's display, and a many feature a connected smartphone or tablet that can keep little ones occupied even if they're too young to fish.
Leading Fish Finder Manufacturers
There are a variety of fish finder manufacturers, but four companies dominate the modern marketplace. Each has its own tendencies, strengths and weaknesses, and it is wise to familiarize yourself with these traits before making your purchase.
Garmin is a US-based manufacturer that was founded in 1989. Garmin is a well-known GPS manufacturer, but they also produce a number of other electronic devices, including fish finders. Garmin produces two lines of fish finders: STRIKER and STRIKER Plus, which are available with screens ranging from 4 to 9 inches.
All Garmin fish finders come with a built-in GPS, and several of their models are equipped with CHIRP sonar, as well as SideVu or ClearVu scanning sonars (and a few of their high-end units provide both SideVu and ClearVu functions). Some of Garmin’s fish finders also come with a number of preloaded maps and charts.
The company now known as Humminbird was originally known as Fulton Electronics, which was founded in Eufaula, Alabama in 1971. They were one of the first mass-market fish finder manufacturers and released their first depth finders shortly after setting up shop.
Humminbird produces several different fish finder lines, including their Helix, Solix, Piranhamax and Fishin’ Buddy series products. The Piranhamax line is comprised of several entry-level products, while the Helix series fish finders are mid-level models. The Solix series contains Humminbird’s most feature-packed fish finders, and the Fishin’ Buddy series is comprised of a few portable units.
Most Humminbird fish finders are available in several different versions, each of which comes equipped with a different slate of features. Several of their series come with GPS capabilities, and advanced imaging technologies, such as CHIRP, traditional scanning sonars and their proprietary MEGA imaging technologies. Humminbird fish finders are available with screens ranging from 4 to 12 inches.
Raymarine is a company with a long and rich history in the fish finder category. They produced their first depth sounder way back in 1923, and have expanded into several other niches in subsequent years. Currently, Raymarine manufactures everything from fish finders to satellite TVs to autopilot systems.
Raymarine produces a single line of fish finders, all of which are referred to as Dragonfly fish finders. These fish finders are available with screens ranging from 4 to 7 inches. Most of their mid- and high-end products include GPS capabilities, and their down-imaging sonar technology (DownVision) is included with even their entry-level units.
One of the most notable features included in most Raymarine fish finders is their optically bonded LCD technology, which provides very high-quality images which are easy to see in all weather conditions. Additionally, their screens are guaranteed never to fog up.
Lowrance is an Oklahoma-based electronics manufacturer, who produces fish finders, GPS units and digital mapping systems, among other things. Founded in 1957, Lowrance played a huge role in the introduction of affordably priced fish finders.
Lowrance manufactures several different fish finder lines, including their HOOK, HOOK2, Elite Ti, HDS Gen 3 and HDS Carbon series. They also manufacture castable fish finders, unlike most of the other leading manufacturers (castable fish finders are typically produced by companies that specialize in those products).
The HOOK and HOOK2 series are primarily targeted toward entry-level anglers, while the Elite Ti series is more befitting intermediate-level anglers. Both HDS series are designed for advanced anglers, and they include a number of high-end features, such as 3D imaging.
Most mid-level and higher Lowrance fish finders come with scanning sonar technology, GPS capabilities and chart plotting functionality. They produce models with a wide range of screen sizes; their most affordable models have 3-inch screens, while their top-of-the-line models feature 16-inch screens.
Charter Captain Tip
If you're looking to upgrade and are already familiar with a unit and how they operate, get an updated model from the same company. You'll get up to speed quicker.
- Capt. Bobby Bourquin
The Bottom Line
It is easy to get overwhelmed by the number of fish finders on the market. There are a plethora of different models available, and the features and capabilities included in the different models vary widely. Additionally, the various manufacturers often use different terminology to refer to similar technology. This all makes it challenging to make apples-to-apples comparisons, and unfortunately prevents some anglers from obtaining the best fish finder for their needs.
However, if you carefully review the information and advice above, you can sort through the confusing language and select the best fish finder for your needs. Just remember to look for a fish finder that provides the features and capabilities that are best-suited for the style of fishing you enjoy, and be sure not to over-buy.
When in doubt about any tech purchase, it's better to go with the choice you perceive as most affordable while still meeting your minimum requirements. Tech buyers report higher overall satisfaction on a perceived good deal than a stretch purchase, regardless of features.