Why is lighting important for aquariums? In its most basic role, aquarium lighting allows hobbyists to observe aquarium inhabitants. But more importantly, proper aquarium lighting provides vital energy to photosynthetic plants and animals. As the primary light source (and in most cases, the only light source), proper aquarium lighting is essential for any system that contains photosynthetic organisms such as plants, anemones, or corals. Lighting also influences fish behavior and physiology and is vital for the overall health and well-being of the entire aquarium.