The algae provide energy for the coral and the coral provide protection and access to light for the algae. Corals can also capture zooplankton as a food source by suspension feeding. Almost all feeding takes place at night so that their tentacles can be retracted during the day when predators could harm them. Also, photosynthesis takes place during the day and tentacles could prevent light from reaching the algae. Reproduction Corals can reproduce sexually and asexually.
Fragmentation can allow for asexual reproduction.
Pieces of coral are broken off by storms and animals and they are scattered to new areas where they can grow. In most cases, sexual reproduction takes place within a given 24 hour period with a mass spawn. The order Montastraea is one that does this. Corals release large numbers of eggs and sperm into the water where the eggs are fertilized and can grow if they reach a suitable place in the substrate. Causes of coral death Before this past century, hurricanes were the major source of damage to the reef.