Trust Fish ID on Humminbird 140C?

Hi all,

I recently got my first fish finder and am learning the different functions on the unit. I'm curious as to whether the fish I'd function (that shows fish symbols when a fish is uniquely identified) is seen as accurate? I've read about a few people that prefer to use the "straight reading", didn't know if accuracy was the reason. When I turned off Fish ID and got into a bunch of sunk wood, I couldn't differentiate small branches from small fish.

Another question: Fish ID will show three sizes of fish symbols. Any clue roughly how big a fish a small/medium/large fish symbol is supposed to represent? (small = minnow size? Brim size?)

The fish symbol is showing you the same thing as the straight line set up. It can't tell the difference between fish and limbs. Size of fish is determined by size and density of object it is reflecting off. I use the symbols on one unit just to tell if something is there. Then switch to see if it is fish, bait fish school or brush. Usually don't pay much attention to it in shallow water. Fish mostly open water so if it shows something usually there is something there to investigate.

There is some criteria that the unit looks for in the sonar returns. It does not blindly assign Fish ID Symbols to all sonar returns. Still it can be fooled. We also give you the option to tweak this by use of the Fish ID+ Sensitivity menu.

If I am remembering right:
Small is a 1 pound fish
Medium is a 3 pound fish
Large is a 5 pound fish
These I believe were all based on largemouth bass that passed through the center of the sonar beam.

cray, thanks for the info. I'll give that a shot.

Humminbird_Greg, I appreciate you chiming in here! After fishing with it the past few days, I want to say you numbers for small/medium/large fish sound about right. I noticed that a medium sized jig or sinker can cause a 'small fish' hit on the fishfinder. Yesterday, I floated across a medium fish on the fishfinder, dropped line and he hit. Pulled up a channel catfish that weighed in just shy of 3 pounds.