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Adaptations and Relationships

Reef Slope : courtesy GBRMPA

Hermatypic Corals live in warm, shallow, water and contains  zooxanthellae algae. Because of the low nutrition content of the water where they live,  hermatypic coral and zooxanthellae have developed a mutual symbiotic relationship (a relationship in which both parties benefit)  so they can survive.  Zooxanthellae algae lives inside the coral for protection from other animals and uses the penetrating sunlight for  photosynthesis to produce food and oxygen.  The food and oxygen leak into the surrounding coral polyp so the coral need not rely on debris floating in the water for its food supply. The algae provides up to 98 percent of the corals dietary needs and  is also what gives hermatypic coral its color.

One behavioral adaptation of hermatypic corals is that if the water temperature rises a couple of degrees, they expel the zooxanthellae algae from their bodies. The corals turn white once the algae are gone, a disease known as "coral bleaching." If enough algae return fast enough, the coral can recover and survive, if not, the coral dies.

Ahermatypic Coral: This healthy branch of Lophelia coral sampled from deep ocean reefs off the coast of South Carolina.

Ahermatypic Corals  are also known as deep water or cold water corals, and they can be found in depths ranging from the warm shallow water just beneath the surface of the ocean where hermatypic corals live,  down to the abyss of 2000 meters (2km or 1.24 mi) where there is utter darkness and the temperatures can be 39° Fahrenheit (4° Celsius). These corals do not have any zooxanthellae algae living with them gaining all their nutrients from debris the currents sweep through their tentacles. These coral do not necessarily have any color.

Potato Cod and Striped Cleaner Wrasse at Cod Hole, Great Barrier Reef

Potato Cod and Cleaner Wrasse- These two animals have a mutualistic symbiotic relationship. The potato cod will sit with its mouth open and the cleaner wrasse will swim into its mouth and gills picking off and eating parasites and left over debris from the potato cod's meals. The potato cod gets rid of annoying parasites and the cleaner wrasse gets a meal. Actually, the cleaner wrasse sets up "cleaning stations" where various large fish come to get cleaned. The larger fish recognize the cleaner wrasse and don't eat it, a fact that some mimicking fish find advantageous, as they mimic the cleaner wrasse. To see a video of a potato cod getting cleaned go to this website :

Clown Fish and Anemone photo:AIMS

Clown Fish and Anemone- This is a very common symbiotic relationship.  The clown fish, since it is unaffected by the anemone's stings, takes shelter in the anemone where predators can't get to it because they are not immune to the anemone's poison. This is mostly a commensal relationship (one species benefits and the other is unaffected) but the clown fish may also act as bait bringing the anemone it's next meal.