Quick answer

A fish finder is a sonar device used on boats or cast from shore to locate fish, measure water depth and map underwater terrain. Its transducer sends high-frequency sound pulses into the water, and the unit measures how long the echoes take to bounce back after striking fish, rocks or the seabed.

A fish finder is a sonar device used on boats or cast from shores to locate fish, measure water depth, and map underwater terrain.  It sends sound waves down into the water via a transducer, which bounce back when they hit fish, rocks, or the seabed.

How a Fish Finder Works

  • Transducer: Sends high-frequency sound pulses (ultrasonic waves) into the water column.

  • Echo Return: Measures the time it takes for sound waves to strike an object and reflect back.

  • Display Screen: Translates echoes into visual readouts showing depth, water temperature, bottom hardness, and fish positions.

Core Features to Look For

  • Traditional 2D Sonar: Great for general depth, speed, and showing fish as distinct "arcs".

  • Down and Side Imaging: Provides photo-like details of underwater structures, logs, and dropped bait.

  • GPS Integration: Marks favorite fishing hotspots and tracks boat trolling speed.

  • Portability: Castable or smartphone-linked wireless options (like the Google Play apps work well for bank and kayak fishing. 

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About Maimun Fishing Tackles. Serving Kenya's fishing community since 1975 (founded as Asma & Sons in Old Town Mombasa) — fishing tackle, nets, aquaculture equipment and farm netting, with branches in Mombasa (Nehru Road), Nairobi (Darosa Plaza, Karen Road), Malindi and Naivasha. Questions about this guide? Call or WhatsApp +254 706 903 465 or email [email protected].