Okay, so you don’t really need a fish finder. Humans have been catching fish without them since before we were humans, after all. However, being adapted to land, we lack the ability to see what’s actually going on under the surface of the water—unless we take advantage of a modern tool, the fish finder.
For most boat-based fishing scenarios, fish finders can make the difference between actually catching anything and just going for a nice cruise. They’re especially useful when you need to cover large territories to find the right species, or if you’re in an open-water situation where you literally have nothing to go on a flat horizon.
That said, fish finders run the gamut from super-simple tools that anyone can operate, all the way up to tournament-style units costing thousands of dollars. The wrong fish finder won’t help you with what you need and can use up all your spare cash, while the right fish finder can be a well-planned purchase that dramatically boosts your catch rates. We’ll help you ensure it’s the latter.
There are fish finders for all anglers these days—and yes, we do mean all. Here are our top recommendations.
What is a fish finder?
Fish finders are just fancy tools that show you important details about the water you’re fishing in so you can make better decisions about how to fish. That, in turn, lets you catch more fish.
At their core, all fish finders have two things: a transducer and a head unit. The transducer sends down sonar waves that bounce back to the boat after hitting things like the bottom, weeds, logs, and yes—fish.
The further away something is, the longer it takes for those signals to ping back to the boat. Those sonar signals, in turn, are analyzed and stitched together by the head unit into one fairly easy-to-read display.
Modern fish finders these days can add on as many extra features as your pocketbook is deep to help clue you in on even more details many fishers find helpful.
Paying more for a fish finder with GPS, for example, lets you mark particular hot spots for fish and can display your trolling speed so you can find the best bite that much quicker, without fumbling around and reinventing the wheel each time you head out.
How does a fish finder work?
All fish finders work by using sonar to create an image of what’s underneath the surface. A basic fish finder creates a 2D image based on how sonar waves are returned to the boat after being sent out in a cone-shaped pattern, centered directly underneath the boat’s transducer.
Fish-finder screens generally scroll from right to left, showing a recording of recent pingbacks—not necessarily a perfect representation of what’s underneath you. Think of it like a polygraph machine, spitting out results over time. If you’re in a stationary boat, the screen will still scroll as the unit continues to send and receive signals, but the screen will slowly morph over time to show an even, steady picture.
Another key factor in how well your fish finder works is its frequency. Higher frequencies—like 200 kHz or higher—create narrow sonar cones under your boat, perfect if you’re in shallower water and want a higher-resolution image capable of picking up more details. Lower frequencies—around 50 kHz—don’t provide as good of resolution, but they can travel further down to where deep-water species like halibut and tuna live.
You can also opt for different types of sonar as well. CHIRP units (short for Compressed High-Intensity Radiated Pulse) are becoming standard and work by stitching together multiple different frequencies into one clearer 2D image.
New technologies like down scanning and side scanning use extra-high sonar frequencies to produce nearly-3D images of the area right below and to the side of your boat, not unlike 3D ultrasound images of near-term babies still in the womb. These powerful tools can allow you to see the shapes of individual bits of structure and the fish hanging out in between.
