Corals are a beautiful addition to any saltwater aquarium and they can also have beneficial effects on the miniature semi-ecosystem that exists in a well functioning aquarium. Further down on this page you will find more detailed articles about coral keeping and different coral species and their requirements. Corals are more complicated to keep than many saltwater fish species, and can for instance require more intricate currents, powerful lighting and supreme water quality. Many corals are incapable of removing their own waste products, and in an aquarium with no current, or with a constant current that moves the water in one single direction, such corals will eventually become covered in waste products and die.
Corals are found all over the world, even around the poles. Reef building corals are however only found in warm subtropical and tropical waters. Reef building corals are present in the Indo-Pacific Ocean and the Western Atlantic. Their habitat is generally limited to the region between 30 degrees N and 30 degrees S latitudes. In the Indo-Pacific Ocean you will find reef building corals from the Persian Guld and the Red Sea, and eastwards in the Indian and Pacific oceans all the way over to Panama and a few places in the Gulf of California. In the Western Atlantic corals are living outside Florida, in the Gulf of Mexico, off the coast of Belize and around the Caribbean Islands, Bermuda and Bahamas. Reef building corals will only live where the water temperature is warm enough; 20-28 degrees Celsius / 68-82 degrees Fahrenheit. Keeping the water temperature in the ideal range is therefore imperative when you keep corals in you aquarium.
Reef building corals prefer quite shallow debts where the light penetration is good and will therefore usually grow at depths of less than 46 metres / 150 feet. The reef building corals require plenty of strong light since they form symbiotic relationship with photosynthetic algae. Other coral species can however survive without direct sunlight and live much deeper down in the ocean. Corals have been found at depths of 6,000 m / 19,700 feet.
As mentioned earlier, your corals will require powerful and intricate currents in the aquarium. In the wild, scientists have noticed that reef development is more profuse in regions where the reef effected by vigorous water movements. Waves and currents bring oxygen to the reef and will also carry food particles to the corals. Currents are also necessary for the reproduction of corals since they transport coral larvae. Without water movements, the corals can also become weighed down by sedimentation.
Most corals require some type of hard substrate to grow on, such as old coral skeletons or an underwater cliff. They will also happily colonise man made objects such as shipwrecks and crashed airplanes. The coral use calcium from the water to build a skeleton that is attached to the surface. The water must be warm and very salty for this process to take place, and the levels of carbon dioxide in the water must be low. This should be kept in mind when you keep corals in saltwater aquariums. In the wild, these three factors will typically be fulfilled in shallow waters.
Aquarium coral - An introduction to aquarium coral.
Black Coral - Information about Black Coral
Fiji live rock - An article about Fiji live rock and its origin.
Growing and Propagating Reef Corals - An article about how to Grow and Propagate Reef Corals
Leather corals - Information about Leather corals.
Stony Corals - Information on stony corals.
Green Toadstool - Sarcophyton Coral
Pulsing Xenia Coral