Fire Coral

While most fire corals are yellow or orange, they can also be found in shades of brown, green, and even blue, providing a vibrant display underwater.

Fire coral has several common growth forms; these include branching, plate, and encrusting. Branching fire coral adopts a calcareous structure which branches off into rounded, finger-like tips. Plate-growing fire coral forms a shape similar to that of fellow cnidarian lettuce corals - erect, thin sheets, which group together to form a colony. In encrusting fire coral, growth takes place on the surface structure of calcareous coral or gorgonian structures.

The gonophores in the family Milleporidae arise from the coenosarc (the hollow living tubes of the upright branching individuals of a colony), within chambers embedded entirely in the coenosteum (the calcareous mass forming the skeleton of a compound coral).

Fire corals are found on reefs in tropical and subtropical waters, such as the Indian Ocean, Pacific Ocean, and Atlantic Ocean and the Caribbean Sea. They are found in shallow reefs where the most sunlight is able to reach them, allowing for a higher rate of photosynthesis of the algae that lives in their tissues. Fire corals thrive in an environment with a high, strong current, and warm water. They are found in almost all places in the world, except for cold coastal regions. They are also abundant on upper reef slopes and in lagoons, and can occur down to 40 meters (131 ft) in depth from the surface.

Fire corals' predatory threats are mainly from fire worms, certain nudibranchs, and filefish. They are also predators to the algae that lives within them, as well as zooplankton/phytoplankton.

Most of the polyps of fire corals can be found embedded in the skeleton. They are microscopic in size and connected by a network of minute canals. All that is visible on the smooth surface are two types of pores: gastropores and dactylopores. These pores work together as a system to capture prey and provide the coral with nutrients. This process starts with dactylozooids, which are long, hair-like stinging polyps that protrude from the dactylopores and possess clusters of stinging cells. These dactylozooids first capture the prey then the prey obtained is engulfed by gastrozooids, or feeding polyps, which are situated within the gastropores. While this method of capturing prey is one form of obtaining nutrients, fire corals also gain nutrients via their special symbiotic relationship with algae known as zooxanthellae.

Fire corals continue to face the many threats that are impacting coral reefs globally, including poor land management, practices that release more sediment, nutrients, and pollutants into the oceans, and other stress on the fragile reef ecosystem. They are also effected by Overfishing, as it has ‘knock-on’ effects that result in the increase of macroalgae that can outcompete and smother corals. Additionally, certain methods of fishing can be destructive to and physically devastate the reef. A further potential threat is the increase of coral bleaching events, as a result of global climate change.