Most fish finder shopping starts in the wrong place: comparing screen size and price before figuring out which category actually fits how you fish. There are three real, distinct categories on the market, GPS combos built for boats, portable/wireless units built for kayaks and bank fishing, and dedicated ice fishing flashers, and they don't overlap as much as the marketing copy on any single product page would suggest. This page is the overview; each type gets its own full guide linked below.
GPS fish finder combos: built for boats
A GPS combo folds sonar together with radar, compass and GPS navigation into one system. That integration is the entire point, you're not just seeing what's under the boat, you're tying that reading to a real position you can mark and return to, or a route you can follow. It only pays off if you're actually on a boat with somewhere to go; a kayak angler working a single stretch of bank doesn't get much benefit from a saved route. See our full GPS fish finder combo guide for screen size and chartplotter tradeoffs.
Portable and wireless: built for kayaks and bank fishing
This category exists specifically for people who don't want to (or can't) permanently mount anything. Deeper's castable sonar units connect over WiFi and Bluetooth to a smartphone app and are designed to be cast out like a lure and reeled back in, scanning depth and bottom structure with no boat required at all, though they can also be mounted on a boat or kayak with optional accessories if you want that flexibility. That's a genuinely different product than a GPS combo, not a stripped-down version of one. See our portable and wireless fish finder guide for the real tradeoffs between this and a boat-mounted unit.
Ice fishing flashers: a category with its own dedicated brands
Ice fishing has its own real, established electronics market, separate from the boat/kayak world entirely, two brands, Vexilar and Marcum, build almost nothing else. Vexilar's lineup runs from entry flashers through its FLX series (FLX-8, FLX-12, FLX-18, FLX-28, FLX-38) up to live-sonar and underwater camera products; Marcum covers the same ground with its own sonar/flasher line (LX-7 G2, MX-7GPS, M-Series Flashers) plus underwater cameras and lithium battery power built for cold-weather use. A flasher isn't a scaled-down graph display, it's a purpose-built format for reading a static hole in the ice rather than a boat moving across open water. See our full ice fishing fish finder guide for how flashers actually work.
| Type | Where it's used | What actually sets it apart |
|---|---|---|
| GPS fish finder combo | Boats | Integrates sonar with radar, compass and GPS in one system |
| Portable / wireless | Kayak, bank fishing, no boat required | A castable sonar connects over WiFi/Bluetooth to a phone app and works with no boat at all |
| Ice fishing flasher | Fishing through the ice | Vexilar and Marcum build dedicated flasher displays and underwater cameras specifically for ice fishing |
Which one is actually right for you
If you own a boat and want to mark spots or follow a route, start with the GPS combo guide. If you fish from a kayak, a dock, or the bank and don't want to mount anything permanently, the portable/wireless guide is the right starting point. If you fish through the ice, skip both of the above, the ice fishing guide covers a genuinely different product category built by brands (Vexilar, Marcum) that barely compete in the other two segments at all. For the underlying sonar technology shared across all three, frequency, CHIRP, side and down imaging, our complete buying guide covers that in one place rather than repeating it on every type page.
FAQ
What are the main types of fish finders?
Three real categories: GPS combos built for boats, portable/wireless units for kayaks and bank fishing, and dedicated ice fishing flashers. They're built for different situations, not different price tiers of the same product.
Can a GPS boat combo work for ice fishing?
Not well, ice fishing flashers are a purpose-built format for reading a static hole in the ice, made by brands (Vexilar, Marcum) that specialize almost entirely in that use case. A boat combo's screen and workflow aren't designed around that.
Do I need GPS if I fish from a kayak?
Usually not as much as a boat angler would. A kayak or bank angler covers less ground and has less use for a saved route, which is why the portable/wireless category, built around castable, app-connected units rather than integrated GPS combos, exists as its own real segment.
Which type should a beginner buy?
Match the type to where you actually fish first, then use our complete buying guide to pick features within that type. Buying the wrong type (a boat GPS combo when you fish from the bank, for example) wastes more money than picking the wrong brand within the right type.
Sources
- [S001] Wikipedia : Fishfinder, (accessed 2026-08-28)
- [S002] Vexilar : official site, (accessed 2026-08-28)
- [S003] Marcum Technologies : official site, (accessed 2026-08-28)
- [S004] Deeper Sonar : official site, (accessed 2026-08-28)