A coral "head", commonly perceived to be a single organism, is actually formed of thousands of individual but genetically identical polyps, each polyp only a few millimeters in diameter. Over thousands of generations, the polyps lay down a skeleton that is characteristic of their species. A head of coral grows by asexual reproduction of the individual polyps. Corals also breed sexually by spawning, with corals of the same species releasing gametes simultaneously over a period of one to several nights around a full moon.
Although corals can catch plankton using stinging cells on their tentacles, these animals obtain most of their nutrients from symbiotic unicellular algae called zooxanthellae. Consequently, most corals depend on sunlight and grow in clear and shallow water, typically at depths shallower than 60 m (200 ft).
LPS Hard Coral LPS Hard corals are "hard" because they are not easily killed. They have sometimes include polyps, branches, or full rock piece....
Mushroom Coral Mushroom corals, also called Corallimorphs or mushroom anemones are very hardy corals, and one of the best for the beginner reef aquarium. Among one of the best beginner corals, they can even be main...
Polyps One of the most indestructible "corals" available to the trade, those from Fiji and the South Pacific are often among the most colorful varieties. These are photosynthetic and require light, and do no...
Sea Fans A Gorgonian, also known as sea whip or sea fan, is an order of sessile colonial cnidarian found throughout the oceans of the world, especially in the tropics and subtropics. Gorgonians are similar to ...
Soft Coral Soft corals, typified by their internal fleshy skeletons, are the most appropriate varieties of stinging animals for the marine aquarist graduating from fish to invertebrate to full-blown-reef enthusi...
SPS Hard Coral The Small-Polyp Stony (SPS) corals have small polyps on a calcerous skeleton. They are usually either branching or plated. For the most part they enjoy bright light and strong currents. They are of...