Gear guide · Tech

Fish finder guide

Castable, boat or live sonar: what each fish finder shows, when it pays off and what you can already see without a device.

How do you want to see the depth?

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Guide sections: Learn to fish: Fish finders

Baits by region Methods Lures Fishing tips Best time to fish Fishing in the rain Rigs Knots Gear Rod types Fish finders Beginner gear Hook size chart Pond fishing Pier fishing

No device or a fish finder?

	Depth map, no device (Pescaday)	Castable	On the boat
What you see	Officially surveyed depth, drop-offs, holes	Depth, bottom, fish below the float	Depth, bottom, fish below the boat, often with a map
Shows fish	no	yes	yes
Where	Lakes and coasts with official data, coarse models elsewhere	As far as you can cast	Wherever you go
Cost	First scan free, then a free account, fine data from Hot Bite	Buy the device, needs a phone	Unit, transducer, power and mounting
Best for	Planning a bank spot ahead	Bank, pier, bait boat	Boat, kayak, charter

The Pescaday depth map is not for navigation, wading or boating.

When does a device pay off?

You fish from a boat or kayak. A boat unit pays off: you see the bottom and fish wherever you go.
You fish from the bank on waters without a depth map. A castable fish finder shows depth and structure as far as you can cast.
Your home water has an official depth map. Start without a device: the Pescaday depth map shows drop-offs and the best bank spot. Buy a device later if you want to see fish.

Fish finder types

Castable fish finderBank, pier and bait boat

A small floating sonar you cast out. It sends depth, bottom and fish arches to your phone. The best-known brand is Deeper.

Boat and kayak fish finderBoat, kayak, float tube

The transducer is mounted on the boat and shows what is below all the time. 2D shows depth and fish, down and side imaging draw the bottom almost like a photo.

Fish finder with GPS and chartplotterBig lakes and the coast

Combo units save spots, draw your own depth maps and lead you back to the drop-off. Worth it if you often fish big water by boat.

Live sonarTargeting single fish

Shows fish and lure moving in real time. The most expensive tech, widespread in the US, for example Garmin LiveScope.

Ice fishing fish finderThrough the ice

Built for the cold, the transducer hangs right in the hole. Shows at which depth fish hold and whether they react to your lure.

Links marked as ad links are partner links: if you buy or book through them, Pescaday receives a small commission. Your price stays the same, and rules and advice do not depend on it. Providers are listed alphabetically; ways without commission, where available, always come first. More (in German)

Quick answers

Do I need a fish finder?

No. From the bank a depth map and plumbing with a weight often do the job. A fish finder pays off on a boat and on waters without a depth map.

What is a castable fish finder?

A floating sonar you cast out on your line. It sends depth, bottom and fish to your phone, so it works from the bank and from piers.

Can I see lake depth without a fish finder?

Yes, where agencies have surveyed the water. Pescaday shows depths, drop-offs and the best bank spot from official data, but no fish.

What is live sonar?

Live sonar shows fish and lure moving in real time. It is the most expensive kind of fish finder and mostly used from boats.