New member with a question regarding side imaging. I fish Kootenay lake for big rainbows quite a bit. We use planer boards trolling bucktails near the surface for the most success. These fish spend a lot of time feeding on schools of kokanee in the top 40 feet of the lake. My question is, will i be able to see fish 20 feet below the surface when I'm fishing in 400 feet of water? Orrr... is side imaging mostly for showing bottom detail? I also plan on using SI on the Fraser river for sturgeon which I'm sure will be just fantastic. Any input would be much appreciated. Tight lines and happy fishing