A lighting fixture and method resist bio-fouling of the outer surface of a window of the lighting fixture when submerged and exposed to biological organisms within a surrounding environment. Ultraviolet radiation is directed to the outer surface of the window from a source inserted within the window, enabling transmission of ultraviolet radiation to the outer surface of the window of an intensity limited to essentially that which is effective in rendering the outer surface immune to adherence of biological organisms to which the outer surface of the window is exposed when submerged, and thereby allowing light from a source behind the window to be projected effectively through the window and into the surrounding environment.
