When a fluorescent tube is fixed over an aquarium, any rays emitted from the top half of the tube are directed away from the water, and are wasted. By using a Giesemann Reflector on the tube, it is possible to obtain the maximum efficiency from the tube, because this otherwise lost light energy is redirected to where it is required, into the aquarium. The Giesemann reflectors are manufactured from sturdy corrosion resistant high glossy aluminium, and the design is such that they can easily be mounted to the aquarium hood.