Yep--most non-bright fish will change color to match their environment, to some extent. Brightly colored fish are usually colored that way to stand out, either to a mate, or to indicate toxins, etc. Fish that are browns, blues, grays, black and greens, are often colored to blend in with the substrate when looked down upon, and many have white bellies so they blend with the sky when viewed from below. Changing colors to match new surroundings improves survival.