At night they come out to feed using their tentacles to sting and kill or paralyse small animals. They then filter the food particles into their stomachs. They can also absorb dissolved food from water. Therefore, their food ranges from tiny animals called zooplankton to organic material in the sea. Polyps are of many different colours and give tremendous colour to the reef when they come out at night to feed.
Many corals have zooxanthellae living within the tissues of the polyps.
These are microscopic algae which manufacture food using sunlight. This food is useful to both the zooxanthellae and the polyps. Coral reefs need constant salinity and pollution -free waters to survive. Malaysia has coral reefs on both the eastern and western coasts of the peninsular as well as off Sabah and Sarawak. Most of these are fringing reefs.