This article is aimed more at aquarists who are interested in keeping corals. Aquarists who decide to keep a fish only aquarium do not need to concentrate on lighting as much as aquarists who keep corals do. Fish only aquarists need to use lighting to create a day/night cycle to provide an inhabitant which the fish feel safe in and also to make the aquarium more visibly attractive to the aquarist.
In a coral only or coral/fish aquarium it is a different matter. The corals utilise the light to gain much needed energy from the light source. Actually it is not the corals themselves it is the symbiotic algae that live within the coral which use the light and provide the coral with energy.
Very much like a ‘thank you for keeping me safe’ kind of thing.
As with the fish only aquarium there is still a requirement to create a day/night cycle so that the aquarium inhabitants are both not engulfed in light as well as being suddenly plunged into darkness.
The trouble is different corals have different lighting requirements. There are some corals which require very intense lighting and other corals which prefer lower levels of lighting. There are even some corals which do not need lighting and gain their energy purely from feeding. These are called non-photosynthetic corals but I won’t cover these in this article.
Photosynthetic corals receive the majority of their energy from the light and the remainder of their energy from actively feeding. As the corals receive so much energy from light it is therefore imperative that the correct lighting be supplied to them.
Aquarium lighting is quite a large topic due to the various types of lighting available, the different spectrums etc. I am not envisaging this article to cover the different types of lighting available but to hopefully provide a little bit of guidance when it comes to ensuring that the correct lighting is installed for the corals you either have or hope to keep.
There are too many times I hear of people purchasing a coral and then attempting to find out what the corals requirements are or even worse not bothering to find out and then wondering why the coral is not thriving or even unfortunately dying.
It is of my opinion that every single purchase made should be thoroughly researched prior to the decision being made to part with your cash. I do appreciate that this is very hard to do and at times is not even possible.
I firmly believe that there are two options available which are covered in this articles title:
‘Base Your Lighting On Your Livestock Or Your Livestock On Your Lighting’
I will cover these one at a time however it is also important to consider the depth of your aquarium. The reason for this is that the colours of the spectrum in the lighting are stripped out the deeper the light has to penetrate.
The following examples are based upon an aquarium which has a depth of 24″.
Base Your Lighting On Your Livestock
In this scenario you have decided upon the type of corals you wish to keep and now you will need to select your aquarium lighting based upon the requirements of your choice of corals.
It is presumed that the aquarist is still in the research stage and has not actually purchased any corals prior to installing all the required equipment.
In the hard only coral scenario you will need to have lighting which is quite strong and has the ability to be able to ‘punch’ the lighting to the entire depth of the aquarium. In this example I would recommend either metal halide lighting or the new LED aquarium lighting. As said it is important to consider the depth of the aquarium. If you do not consider this and purchase lighting which is not strong enough then the lighting which is at the bottom third of the aquarium may not get enough light and therefore any corals you place in this area will not get enough light.
In the soft coral scenario you will still need to have lighting which is of the correct spectrum however you will not need lighting which is as strong as the metal halide/LED lighting option. The reason for this is that whilst soft corals do still need a good amount of lighting it does not need to be as strong as hard corals require. In this scenario I would recommend using either T5 or T8 lighting.
In the mixed hard/soft coral scenario then you need to be a little more careful. The reason for this is that these two types of corals require different strengths of lighting. The reason why you need to be careful is in relation to the placement of the corals in the aquarium. If you place a hard coral too low down in the aquarium then there is a risk that the coral will not receive enough light. If you place a soft coral to high in the aquarium then there is a risk that the coral may receive too much light and actually could get burnt. In this scenario the recommendation would be that you can use either metal halide, LED lighting or even T5 tubes as long as you can place enough of the tubes in the hood. As said though in this scenario you need to ensure that you place the corals in the correct position so that they receive the correct amount of light based upon their requirements.
Base Your Livestock On Your Lighting
This option is my preferred option as you are able to setup all of the equipment required prior to even considering the actual purchase of a coral however I do appreciate that a lot of people do actually set up their aquarium based upon what they know they want to keep and for this I applaud them.
OK, let’s have a look at some of the lighting options available:
T8 Lighting – With this type of lighting you will need to put quite a few tubes into the hood in order to give good coverage of light. It is recommended that you utilise an even split of white and actinic tubes in order to give a good colour spread. T8 lighting whilst economical do not provide that much power and therefore cannot push the light that far down into the aquarium. For this reason it is recommended that you only consider keeping soft corals with this type of lighting.
T5 Lighting – T5 lights are very similar to T8 lights with the exception that they are slimmer in design and are slightly more powerful. As with the T8 lights it is recommended that you install an even mix of white and actinic to give a good colour spread. At the top of the aquarium (about 6″ inches or so) they have a good amount of power, however further than that they have about the same power of a T8. For this reason you should be able to keep certain types of hard corals in the upper quarter of a 24″ deep aquarium and soft corals under that. Certain LPS (Long Polyp Stony) corals may be suitable to thrive in the mid/lower regions however I would recommend that you check their requirements prior to committing to a purchase.
Metal Halide/LED Lighting – This type of lighting is the most powerful and there are a vast variety available in relation to the power types available. The power as with all lighting is based upon the watts. The higher the wattage the more powerful the lighting is and the further into the water the unit can push the light. Using this type of lighting you should be able to keep both soft corals and hard corals; however you will need to ensure that the corals are placed in the aquarium in a location where their light requirements are met. For example you would not want to put a soft coral at the top of the aquarium as it would receive too much light and could even get burnt.
It is exceptionally important that the correct environment be created for the corals which are being kept. Not just lighting but also water movement and the actual physical placement of the coral.
When in the store looking at making a purchase do not be afraid to speak to an employee of the store and ask if the coral(s) in question are suitable for your aquarium. Inform them of your lighting and they should provide you with the correct information for you to base your decision upon. I say should as unfortunately there are some stores who will just say ‘Yeah, that will be fine’ just so that they can get the sale. The majority of stores are not like this and have a huge interest in the well being of the animals they sell but unfortunately there are some that do this. My recommendation if this happens – walk away and purchase elsewhere.
It should also be noted that proper acclimatisation techniques should always be followed – not just in relation to actually transferring the coral from the shop to the aquarium but also correctly acclimatising them to the light.