The Great Barrier Reef is the world’s biggest single structure made by living organisms. It supports a diversity of life, including many vulnerable and endangered species, some of which may be endemic to the reef system. Here are a few from the multitude of exciting undersea creatures you will encounter in the largest coral reef system in the planet.

Stonefish

Meet the most venomous fish in the world! They live in the sea (primarily above the Tropic of Capricorn) always so well-disguised, looking like a crusted rock. They are usually brown or gray and occasionally have patches of yellow, orange or red. It has potent neurotoxins secreted from the glands at the base of its 13 needle-like dorsal fin spines. It snacks on fishes and crustaceans by waiting for them to swim by and strikes them with incredible speed that lasts for 0.015 seconds.

Giant Clam

The Great Barrier Reef is home to many species of giant clams including the Tridacna gigas or simply called “giant clam” which is the largest living bivalve mollusk, capable of reaching up to 4 ft (1.2 m) in length and weighing more than 500 lbs (227 kg). Once this bottom-dwelling creature finds its spot in the seabed—it stays there for the rest of its life.

Wobbegong Shark

This bottom-dwelling shark spends much of its time resting on the sea floor. Wobbegongs are also called carpet sharks due to the fact that they are well camouflaged with their symmetrical patterns of bold markings resembling a carpet. This nocturnal hunters are not dangerous unless they are provoked.

Humphead Wrasse

Cheilinus undulates, more commonly known as humphead wrasse, Maori wrasse, Napoleon wrasse and Napoleonfish is one of the largest reef fishes with males reaching up to six feet in length. It is mainly found in the coral reefs of the Indo-Pacific Region. It has thick, fleshy lips and a hump that forms on its head above the eyes, becoming more prominent as the fish ages. It changes in body form, color and sex during its lifetime of at least 70 years. This fish is included in the IUCN Red List of Threatened Species.

Sea Cucumber

Sea cucumbers are cylinder shaped animals that live in seas worldwide. The body of this echinoderm is elongated, leathery and muscular with spines in its skin. Surrounding the mouth are 8-30 tentacles. These brainless creatures feed on decaying matter in the sea. To confuse predators, it expels most of its internal organs which it later re-grows. These nocturnal things have a lifespan of up to 10 years.

Cuttlefish

The cuttlefish is a mollusk, which means that they are more closely related to slugs and snails than to fishes. They belong to the Cephalopoda group of animals which include squid and octopuses. This intelligent invertebrate have a gas-filled shell called a cuttlebone which allows them to be buoyant. They have large W-shaped pupils and eight arms plus two tentacles equipped with suckers with which they use to secure their prey which include crabs, shrimps and fish. This ambush predator is a master of disguise with far more superior ability to change skin color and texture than the chameleon. They have a rather short life span of only up to two years.

Lionfish

This brightly colored red and white stripped fish is usually found in rocky crevices and coral reefs of the Indo-Pacific waters. Its 10 needle-like venomous dorsal fin spines can produce painful puncture wounds. Despite the fact that it is one of the most poisonous fish in the world, it is considered a delicacy in some countries and is most prized in the aquarium trade due to its spectacular striking appearance. This daytime hunter is also known as turkey fish, dragon fish and scorpion fish.

Moray Eel

These nocturnal predators come in a wide variety of colors and patterns. Contrary to its vicious-looking appearance, it is in fact a shy and reserved marine creature which will only attack humans in self-defense. Moray eels cannot see nor hear well but they have a good sense of smell. Their skins are thick, scaleless, camouflaged and coated with protective mucus.

Sea Anemone

This spineless plant-like creature is in fact a meat-eating animal that thrives by attaching itself to solid objects in the sea bed such as a rock or coral. Sea anemones come in a wide variety of colors, shapes and sizes. They feed by waiting for fish, mussels and worms to swim by and sting them with their tentacles which inject a paralyzing neurotoxin.

Clownfish

The Clownfish is a small and brightly-colored orange fish with three white vertical stripes. It calls the anemone “home” thus earning its other name, the Clown Anemonefish.  While the tentacles of the anemone can kill fish that touch them, this fish is believed to be coated with mucus that protects them from the deadly poison. This pair have a symbiotic relationship with the anemone protecting “Nemo” from predators and the fish gives back by being a house cleaner.

*All images taken at The Great Barrier Reef by Leonard Low.

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