I've never used one fishing but I'm thinking about getting a portable one to try and see how many fish are swimming in my ponds and the approximate depths. Kind of a relaxation and hobby thing. I see the prices vary widely and, as with most things, I'm sure the more expensive ones are better but does anyone have any experience with them? My deepest water is about 12 feet and just wondered how good of one would I need to pick up the blips of the fish pretty accurately. I have an Aquavue camera which would be nice in clearer water but I can't see much in my ponds unless a fish swims a foot or so away.