The Great Barrier Reef is teeming with a variety of beautiful sea life!
The Great Barrier Reef can be found off Queensland’s north-east coast in Australia’s tropics. This spectacular part of the world has been added to the World Heritage list and is hence a protected area.
Did you know that the Great Barrier Reef is not just one big reef? In fact, it is made up of almost 3,000 smaller reefs and around 900 islands that stretch along Queensland’s coast for more than 2,600 kilometers (1,600 miles)!
These reefs are home to a wide variety of marine life, including fish, turtles, whales, sharks, hard and soft corals and much more.
In this post on the Reef, we will look at 12 Aussie marine creatures. Let’s begin with the famous, cute, little orange clown fish.
01. Australian Clown Fish
The movie “Finding Nemo” has made the Clown Fish one of the most famous fish around! In fact, I must admit that the clownfish has always been my favorite fish! It always makes me smile, as it looks so cute.
If you look closer into clown fish, you will find that there are approximately 27 different species worldwide. Some of these species live in Australia’s Great Barrier Reef.
Clown fish are only a small fish that grow to between 6-18cm (2-7 inches) in length. They also can live up to eight years of age.
Did you know that all clown fish are born as males? They only grow into a female if their family needs one to make babies.
A special relationship exists between the clown fish and the sea anemone, which is where they make their home. Each clown fish family lives in and around one anemone.
The sea anemone is a marine creature that is dangerous to most other sea life. It uses its toxic venom to paralyse its prey and then eats it up! One exception is that the sea anemone lives in harmony with clown fish and acts as a protection for them from other predators. So it is a pretty cool relationship and great for the clown fish’s safety in the reef!
Each clown fish family is made up of the dominant male, one female and some young males that have been born into the family. This one female lays all of the eggs to produce the baby clown fish.
It is only when the female dies that the dominant male then changes into a female and he begins to lay eggs to keep the family going.
Clown fish are omnivores. They like to eat algae and plankton. This small fish also helps to keep the sea anemone clean by eating any bits of food that are not fully digested by this companion creature.
02. Blue Tang Fish
In the movie Finding Nemo” one of Nemo’s friends is Dory who is a Blue Tang Fish. This fish is a beautiful, bright blue color with a small, yellow tail.
It is interesting to know that as the blue tang fish grow older they change color. They start off as young fish that are mainly yellow with some blue spots. Then as they grow into adults they change to mainly blue in color with a yellow tail.
Blue tang fish can grow up to 30cm (12 inches) long. They get very hungry and need to eat lots of algae and also plankton each day.
If you ever catch one of these fish on a fishing line, then be sure to quickly throw it back into the water. Do not eat them, as their flesh is poisonous!
Did you know that the fish actually help the health of the reef by eating the algae that grows on the coral? This stops the algae from suffocating the coral if it was to get too thick!
03. Soft Corals
Commonly found throughout the Great Barrier Reef system is a variety of different Soft Corals. These are small animals that don’t have any rigid skeleton.
Soft corals do not need as much sunlight to grow as the hard corals do and so they can be found in much deeper water.
Their main food source is plankton, which floats past in the water. Since the soft corals only have limited movement it is very hard to grab the passing plankton. As a result of this, the soft corals also carry out a bit of photosynthesis, which gives them a substantial boost of energy.
These coral systems are a great place for many fish to live and hide.
Soft corals come in a wide variety of different colors and shapes. Some are branched like a plant, others are flat like a fan and still others form all different shapes and designs.
04. Hard Corals
Hard Corals, often referred to as Stony corals, are a type of coral that has a hard skeleton. They reside only in tropical waters and are part of the main construction of the Great Barrier Reef.
When the coral reproduces it will form a number of free-swimming polyps. Some of these swim away and form their own coral structures. While other polyps stay close by and make the existing coral structures even bigger.
There are many different corals in the Great Barrier Reef, each contributing to the dazzling colors and shapes.
Hard corals can be quite delicate and brittle. In some areas on the reef where tourists come to swim and dive it is possible to see whole areas of dead coral where people have stood on it and broken it all up. Damage also happens when big storms and cyclones occur.
05. Giant Clam
The Giant Clam, as the name suggests is huge. In fact, it can weigh around 200kg (4401b) and measure approximately 120cm across (47 inches).
Did you know that giant clams are actually the largest of all mollusks in the world?
Giant Clams can be really stunning in color when they are open. Beautiful, bright blues, purples and greens make it quite easy to spot these reef creatures when diving or snorkeling in the water.
These clams are able to live up to 100 years old. which is quite amazing for such a sea creature! But still the giant clam is critically endangered within the Great Barrier Reef, with the numbers shrinking each year despite efforts to help preserve this animal.
The main source of food for the Giant Clam is algae that can be found in the water around the clam.
One of the unique things about the Giant Clam is that they have a special system in place that circulates these algae around their body without digesting it, which ensures they get the highest possible amount of nutrients quite quickly.
06. Australian Seahorses
Seahorses, as you can probably guess are named for their very distinctive shape, with a head that resembles the shape of a horse’s head. They are actually in the fish family.
There are lots of different species of sea horses around the Great Barrier Reef.
Despite living in the sea, they are very poor swimmers and most of the time they stay still with their tail wrapped around something stationary.
When the sea horse stays still on a plant or coral it usually blends in so well that it is very difficult to even see it! Some sea horses actually look like a plant themselves! This great ability to camouflage themselves protects them from predators.
Fish, crabs and stingrays are all marine animals that kill and eat the defenseless sea horses! In other parts of the world penguins are also major predators.
Look at this beautiful Sea Dragon. Sea dragons are related to Sea Horses and are also fish.
Probably the worst predators of all for sea horses are human beings! Pollution and the destruction of the coral reef where the sea horses live mean that many perish each year.
One of the key features of the seahorse is that it is actually the male that carries around the eggs. The female deposits them into a pouch on the front of the male and he protects the eggs until the babies hatch.
However, the male will not care for the eggs once they have hatched. The baby sea horses are on their own once they leave the safety of their dad’s pouch.
Do you know what a baby sea horse is called? It is called a Fry.
Nudibranchs are sometimes called sea slugs and they are known for their incredibly beautiful colors. They belong to the family of Mollusks, which includes snails, slugs and octopus.
The word Nudibranch is pronounced “Noo – de – brank”. The “ch” at the end makes a “k” sound.
There are thousands of different species around the world with many inhabiting the Great Barrier Reef system. The colors and shapes are truly amazing and beautiful to look at.
They live at all depths of the water, although you will find that many of them live near corals on the reef.
The main reason for their color is that it acts as a defense mechanism. Basically, they are able to blend in within the variety of plants in the area and their bright colors warn predators that they are toxic.
Sea Slugs are unique in the fact that they are both male and female. However they are unable to fertilize themselves and do need a partner in order to produce babies.
Did you know that Nudibranchs are carnivorous? This means they eat other animals. Some of the things that Nudibranchs eat include fish eggs, anemones, sea sponges, coral, as well as other sea slugs and nudibranchs!
Just one last point on these colorful critters, all nudibranchs are sea slugs, but not all sea slugs are nudibranchs. Some sea slugs belong to a different family of mollusks.
08. Australian Blue Starfish
The Australian Blue Starfish is one of the most common starfish found in the Great Barrier Reef. As you can probably guess from their name, they are bright blue in color.
Of course, they are not technically a fish; they are actually a sea star. So another name for this pretty sea creature is a blue sea star.
They each have five arms. If one of these is broken off, it can grow back rather quickly.
Perhaps one of the key features though is that a broken arm can actually develop into another Australian blue starfish (sea star) all by itself! This is really quite amazing!
They mainly eat algae and other food scraps that are found on the ocean floor. This includes organic matter from other marine animals that have died and are decaying. Sea stars also like to eat the soft insides of mollusks that live under the water.
The blue starfish does have some enemies. Predators that eat this creature include sea anemones, puffer fish and some shrimp.
09. Green Sea Turtle
The Green Sea Turtle is a turtle that can be found on and around the Great Barrier Reef. It gets its name from the “green fat” that is stored under its shell and the greenish colored skin. Sometimes there are also algae growing on the turtle’s shell that also makes it look green.
This particular turtle is the biggest of all sea turtles in the world. These cute animals begin life as tiny little baby turtles only about 6 cm (2 inches) long.
As an adult it can grow up to 1 meter (3 foot) in length!
The turtles that come close to the shore in Australia are adult turtles. It is very rare that young turtles will come close to the shore, after they have hatched and headed out to sea. Instead they will spend the first five years of their life out in deeper waters.
When the green sea turtles are young they eat jellyfish, crabs and small fish. After they have grown into an adult these turtles are herbivores and live mainly on algae and sea grass. The turtle’s short beak has a saw-like edge that allows it to easily cut off the sea grass that it wants to eat.
Did you know that green sea turtles sleep underneath the water? In fact, they can stay under the water for hours while they are asleep.
Green sea turtles can live a long time if they survive all of the dangers when they are young. After hatching from their egg they need to crawl across the sand all of the way to the water’s edge.
Many birds and other animals wait for them to hatch so they can eat them. So not all of the babies make it to the water. Those that survive have been seen to live longer than eighty years, sometimes even up to 100 years!
All turtles are endangered and need our help to survive into the future!
10. Blacktip Shark
The Blacktip Shark is a shark that favors locations with tropical warm waters, hence why it can be found in and around the Great Barrier Reef.
One of the more intriguing things about this particular shark is that it is one of the few species that can leap up out of the water. It normally does this when it is feeding. This behavior has especially been seen when the shark is near to a school of small fish and it is trying to catch its meal.
Small fish make up most of the blacktip shark’s diet, but they also eat other sea life as well. These sharks can also enjoy eating stingrays, skates, other small sharks and even small crustaceans, such as shrimp and prawns.
Attacks on humans are incredibly rare, although they do happen. This is true since these sharks often live where divers and swimmers are also found, especially around reefs. It is also very common for people to swim beside these sharks with no problems at all, as they are usually quite peaceful and docile.
Blacktip sharks prefer to swim in shallower waters. Hence they are often found quite close to the shore. But they are also good divers and if they want to they can dive down into deep waters.
These sharks are sociable, but they tend to stay in groups of their own gender, hence males stay with other male sharks and the females with the females. When it is time to mate to make babies they then visit the other gender.
11. Spinner Dolphin
The Spinner Dolphin can be found in many ocean waters around the world. One of these places is around the Great Barrier Reef area in Australia.
Every so often, a few of these small dolphins will treat people to fantastic acrobatic displays as they leap out of the water, spinning at the same time. They certainly are a wonderful sight to behold and this is why these creatures are called the natural acrobats of the sea!
They are a gorgeous looking, slender dolphin with a very long beak. Males grow to a maximum length of around 2.3m (7.5 foot) and females are slightly shorter at about 2.1 m (6.9 foot).
The females give birth to a dolphin calf about every two to three years. Calves start their life at approximately 0.8m (2.6 foot) long.
They stay close to the side of their mother, drinking her milk to grow big and strong. When the calf is about six or seven months old it stops drinking its mothers milk and then enjoys a lifetime of eating fish.
The spinner dolphins dive down to depths of 250 meters or more and this is where they eat most of their food. They mainly eat small fish, but also enjoy shrimp and squid.
Research has shown that the spinner dolphins that live near the Great Barrier Reef are diurnal. So during the day they gather together close to the shore. Then around dusk they head out to the deeper waters to feed.
The Dugong is an incredibly large marine animal that lives around the Great Barrier Reef.
Often people refer to them as sea cows. This is mainly because of what they eat. Generally speaking, they will only eat sea grass and not very much more. If there is not much sea grass available then dugongs also eat algae.
They are one of the longest living animals in the Great Barrier Reef, often reaching the age of over 70. This is mainly because of the fact that there are very few predators out there who are after it, probably due to its large size.
Young dugongs try to hide behind their mother when in danger, but killer whales, crocodiles and sharks sometimes still eat them!
Dugongs have also always been a food source for native indigenous aborigines that live around these coastal areas.
At the moment their numbers are threatened, with some people hunting them for their precious fat. Dugongs also sometimes drown after becoming caught in fishing nets. Some of the sea grass habitats have also been threatened, which impacts the dugongs directly since this is their main source of food!
Dugongs spend a lot of time under water searching for food, but they still need to swim up to the surface to take a breath regularly.
It is interesting to know that dugongs are similar to their cousins the Manatees. The main difference between the dugong and manatee is the shape of their tail. Dugongs have a tail similar to a dolphin or whale. Manatees have a tail that is like a rounded paddle.
We have just looked at 12 of the marine animals that live on and around Australia’s Great Barrier Reef in this article, but there are many more that also swim in these warm, tropical waters.
I hope that you have learned something that you never knew before about some of the world’s amazing sea life.