How to succeed with marine corals in your reef aquarium
If you have already set up a successful marine aquarium with a host of saltwater fish, live rock, and perhaps even a few invertebrates, you might be entertaining the possibility of keeping marine corals in your tank as well. While you may have heard that keeping corals in your reef aquarium is a difficult task, it can be a vastly rewarding experience if it is approached correctly. And may not be too big a step up from the set up you already have if your marine aquarium has been running for quite a while.
Consider what your set up offers
As always, a larger tank will provide you with a sufficient volume to reduce eventual problems with water quality management. If you are fortunate enough to be the owner of a large tank, you will find that the health of your fish will be easier to manage during the period when you introduce corals to your tank. The larger your tank is, the better you will be able to adapt it to the presence of coral colonies.
If you already have high quality filtration and an adequate lighting set up, you are well on your way to enjoying a successful reef tank. In terms of filtration, you will need a greater amount of water flow throughout your tank than you may currently have, since corals are immobile and will need to draw their nutrients from the water itself as it passes through them.
Your aquarium’s lighting set up will have to closely replicate natural sunlight: a spectrum of blue UV light for 12 hours a day and a full spectrum white light for 8–10 hours a day would be the minimum for ensuring a healthy coral population in your reef aquarium.
Water quality and management
The ideal temperature at which most marine corals will thrive is between 23–25° C, with 25°C representing an optimum temperature for coral tanks. Temperature is very important due to the effect that warm water will have on the level of dissolved oxygen present: Oxygen level will decrease with higher temperatures, causing respiratory problems for your corals.
The most dependable way of keeping your water temperature constant is through the use of a refrigerating chiller with a temperature gauge. While it is possible to maintain the appropriate temperature without a chiller in many circumstances, you may want to use one in order to give your marine corals the best opportunity to thrive.
If you have a quality filtration system in place in an already cycled tank, you will not have to worry too much about ammonia, nitrite, and nitrate levels, but organic compounds could become a problem if they are allowed to break down into harmful waste products. The use of a protein skimmer can be a great help when keeping a coral reef aquarium.
Corals tend to do their best with a pH level between 8.0–8.3. You will want to test your water regularly to ensure that the levels do not change after you introduce corals to your tank, since they can upset this delicate balance of water acidity and harm your entire tank population in the process.
One of the key indicators that aquarists use to determine whether their tank is ready for the introduction of live corals can be seen in the live rock already present: When your live rock begins developing spots of purple, this indicates the presence of coralline algae, which grows as a result of the same conditions necessary for the growth of marine corals.
Choosing and introducing live corals to your tank
Once you have the appropriate conditions ready, you can introduce your corals to the tank. Proper coral choice is important here, since dissimilar species of coral can be very difficult to maintain. Two basic types of corals commonly found in reef aquariums are as follows:
- corals, which feature a hard exoskeleton and are also often called hard corals, and;
- Soft corals, which do not have an exoskeleton and often inhabit different waters then their stony counterparts.
You may be tempted to mix these two types of corals, but you are recommended to stick with one or the other for your first coral experience. You should thoroughly research the species you would like to incorporate in your tank to make sure they are compatible—coral competition and aggression is not uncommon in reef tanks.
Soft corals are generally easier to care for then stony ones, although not always: preferred choices include any of the following species:
- Finger leather coral
- Pulse coral
- Jasmine polyps
- Star polyps,
- Clove polyps
- Cabbage leather coral
If you would prefer stony varieties, peaceful stony corals such as the popular candy cane coral can make an excellent choice for your first foray into keeping a coral aquarium. Also, whisker coral, also known as Duncan coral, can make a fine addition. Bubble coral is easy to care for but can be aggressive in temperament.
Once you have your tank prepared and have purchased your desired coral fragments, you are ready to attach them to the interior of your tank. Specialized aquarium glue exists for exactly this purpose, and can help make the process much easier than attempting to secure the coral with toothpicks and hoping it sticks.
Coral placement depends on the strength of your tank’s lighting and your corals’ specific needs. Marine corals may need to be gradually acclimated to your tank lights, which can be done by placing them at the bottom of the tank at first and then gradually moving their foundation upwards over the course of a week.
Once you attach the corals to the interior of your tank, you will have to carefully monitor the water conditions in order to make sure that no abrupt changes take place. This, along with regular maintenance, will ensure a long and healthy life for your corals.
Coral maintenance and care
Once your marine corals begin getting accustomed to their new lives inside your reef aquarium, you will need to take care of them in order to ensure lasting success with your reef aquarium. You should be testing your water weekly for pH changes as well as ammonia and nitrite levels, and have a cleaning routine ready that includes both your filtration system and your lights as well.
Some species of corals have more specific feeding and maintenance needs than others, but if you choose to keep varieties of coral that require the weekly addition of coral food, the trace elements you should generally add include calcium, strontium, iron, and magnesium. Other than this, your monthly partial water change schedule should run normally.
Responsible coral harvesting
As a last word on keeping a successful coral aquarium, you should be aware that there are two types of coral suppliers in the aquarium trade: those that are licensed by the Convention for International Trade in Endangered Species (CITES) and those that are not. Licensed providers cannot exceed an annual quota of coral sales, and are compelled to source fragments from sustainable areas.
Licensed suppliers also contribute to marine conservation, and you should always purchase your coral fragments (or whole live corals, if your budget permits) from these vendors. Unlicensed coral sellers can do enormous damage to already endangered natural habitats.
If you follow this guide and choose your marine corals carefully, you should be well one your way to enjoying a beautiful and colourful coral display in the comfort of your own home. Remember that some species such as the clown fish live between the fronds of coral. And so will make a lively display. Sit back relax and enjoy the show!