Silver salmon and steelhead trout approximately one year old were tested in an experimental flume with velocities of 3.9 and 1.5 fps, with different amounts of infrared light behind a 20 degree angled barrier. It was concluded that the fish either were not sensitive to infrared light at the three intensities used, or they were not repelled by it. The use of infrared sources and converter image tubes may therefore be used safely to observe the behavior of these fish while making other sensory discriminations in darkness.