When we humans enter a dark room, we turn the light on to enable us to see. Intelligent technology! That, of course, is not the reason for the importance of marine reef aquarium lighting, though we do need to see inside the aquarium.
Ok, but what about fish aquariums? These are not so critical with lighting, but the reef type aquarium lighting could enhance many of the fish colours. There is plenty of choice, but the choice isn’t so critically important.
The reef aquarium is made up of (maybe) sand, rocks, fish and corals. It is the latter that are so demanding of light, not all of them but a large number. When purchasing a coral the dealer should be able to advise if there is a need for ‘proper’ lighting, an alternative is a good book or the internet.
Lighting is the number two requirement for the reef aquarium on a list of importance, the number one is seawater quality. If seawater quality is poor then the captive reef will not be as hoped for.
Correct reef aquarium lighting is not difficult to achieve. Nowadays one of the best for home aquariums is LED which can be purchased in the same shape as a fluorescent tube, or as a direct replacement for the same. There are other formats of course, such as flat plates etc. The only additional need is to obtain the correct spectrum which is usually made clear by the manufacturer. Technical knowledge is not required – for example, one manufacturer describes lights as ‘marine white’ and ‘marine blue’. Obtaining half the required tubes in marine blue and the other half in marine white is usually fine. Plate type lights usually remove the need for this split, as white and blue bulbs are in place already.Well, no difficulty there! But why is lighting so important for the captive reef? Obviously not for the rocks etc! Nor for the fish. It’s the corals that require the lighting to be healthy as they have zooxanthellae in their flesh and these zooxanthellae are essential for the corals health. The lighting spectrum needs to be correct so that the zooxanthellae are able to make use of it.
Zooxanthellae have a symbiotic relationship with corals. It’s likely that the zooxanthellae produce oxygen and carbohydrates which is taken up by the coral and the coral’s waste products used by the zooxanthellae. Zooxanthellae are like algae, but very small – in a square inch of surface area there could be millions. In addition, zooxanthellae assist in the collection of important trace elements from the surrounding seawater. It seems clear that the zooxanthellae, like other plants, use photosynthesis to produce food. If the zooxanthellae are in trouble because of poor lighting (or poor seawater) then so is the coral.
Not all corals have zooxanthellae. When buying a coral, the dealer should be able to advise. As already said, a modern good book or going on-line can give the information about a particular coral.
It’s been said many times that basic research is needed for success. Again as said, there isn’t any need for horn-rimmed glasses and a white coat! Do the basic research to check if the coral has zooxanthellae, get the correct lighting, maintain high quality seawater, don’t overload the aquarium with too many fish and don’t overfeed. Finally complete the ongoing maintenance requirements such as partial seawater changes, cleaning etc. If the corals fail to survive in good health, if the fish are in poor shape, it is Mother Nature complaining. Do the small amount of research and the very easy ongoing maintenance as required and the rest should be automatic – a beautiful, interesting and very natural looking reef.