Reef building coral cannot live in water temperatures below 64° Fahrenheit and prefer to live in water between 73° and 84° Fahrenheit. The water also needs to be clear in order to get the light needed for there photosynthetic algae called zooxanthellae. The coral is a protective home for this algae and return the algae is its food source.
Coral reefs are found around the world with most being located between the Tropics of Cancer and Capricorn. Corals can be found as far down as 300 feet but most will be above 60 feet. There are cold water corals found outside of this range but they are few and are not reef building coral.
Coral needs stable water parameters. Water which is unpolluted and not diluted by fresh water from river openings and run-off is best.