Its really simple; buy the best fish finder you can afford.
You pay for.....Power, screen definition, and color, In some combination.
The better of each you get, the more you pay.
The basic ones show depth to something over 200ft in salt water, structure, bait. But sometimes it is tough to see fish vs kelp, etc. Also, it takes power to see a fish down deep in salt water.
Finally, if you stretch for a nice one, get a nice warranty....The kayak environment is really tough on this stuff...
Good luck
Cowboybill
