Its very full. Do realize as you mentioned light that the coloration of coral polyps and tissues is dictated by zooxanthellae. By differing the spectral output of our tank lights, we can actually influence the ultimate color/shading of our corals. They require a level of photosynthesis in order to survive. Just as plants convert sunlight to produce chlorophyll, marine animals survive similarly by converting light energy into food and this energy is consumed by zooxanthellae algae which produce by-products that the corals need to survive in a form of symbiotic relationship.
The coral's color is actually that of their hitch-hiking algae adapting to the increases or decreases of ultraviolet and other energy-source factors.
