I’ve used mine in the boat and under the ice. Once you get over 15 feet of water it’s pretty dark. I’ve used it in 25 feet ice fishing and I can only see about an inch or two from the camera.
I have located clam beds and a mess of bluegills last year using a camera.
I bought one last spring but haven’t really given a good try on the river… I did play around with it a few times and found that cranking the lights on the camera helped a great deal with getting a better picture – can be kind of light running high-beams in a snow storm, though, if the water is full of ‘floaters’. Play with the level until you get the best image. (I have an AquaVu Scout).