The evolution of the present day corals began 50 million years ago, the warming and cooling of the earth has caused numerous sea level changes.  During the last Ice Age, what is now the Great Barrier Reef were limestone hills and grassy plains.

There are 2 main types of corals, hard and soft corals. Coral formations (colonies) consist of many individual polyps.  A coral polyp is a simple jellyfish like animal.  In hard corals the polyp is covering a cup of limestone which is secreted by the polyp. The soft corals lack the rigid limestone skeleton.

Corals grow in warm clear water which is why coral reefs are found in tropical and sub-tropical climates.  In order to thrive they require:

• Sunlight
• Clear shallow water
• Low nutrient levels (to prevent plants from competing)
• Stable salinity (salt content)
• Warm water between 22-29 degrees Celsius
• Hard surfaces to grow on
  
  

There are 400 species of coral.  Some of the common hard corals are easily identified by their appearance such as Boulder, Branching, Plate, Brain, Mushroom and Vase corals.

Soft corals have feathery tentacles and usually inhabit deeper areas on reef walls where currents bring plankton to them to feed.  Soft corals may be delicately branched, vibrantly colored and softly swaying or lobed and leathery. Included in the same class as the corals you will find blue corals, sea whips, sea fans and sea pens.  Every trip on HABA guarantees a multitude of color and variety for your viewing pleasure.