The Must See Great Eight of Marine Life on the Great Barrier Reef

Christina James on May 9th, 2018

Have you heard about the Great Eight must see marine life on the Great Barrier Reef in Australia? If not continue reading as these are the marine animals you simply must not miss when you book a snorkel and dive trip for the day or an extended overnight dive and snorkel tour on the Great Barrier Reef.

With the changing of seasons and varying water temperatures during the year you will see how the underwater marine life have a changing of the guard coming and going as they all migrate to the Great Barrier Reef for various reasons.


The giant Humpback Whales and Dwarf Minke Whales make their way along the eastern seaboard coastline of Australia during the months of May to September finally making their way to the northern parts of the reef to calve in the safety of the coral waters away from the predators that are normally not too far behind following their migration paths for any opportunity that may come their way.

Visitors can book a one day reef trip for whale watching, swim with whales and extended overnight dive trips to scuba and snorkel with the Dwarf Minke Whales in various locations along the Great Barrier Reef.

Potato Cod Fish

Giant Potato Cod fish are the puppies of the Great Barrier Reef.

In specific dive locations they have worked out the precise time and precise day that a boat load of divers and snorkelers will be visiting their patch of reef and they eagerly await the visitor’s entry into the water to get some good selfies with the tourists.

The Potato Cod fish had this name given as their skin represents potato shaped markings.

These fish can grow up to the size of a diver at 2.5m and weigh 100kg.

These fish are now in danger because of their friendliness and the opportunistic fishermen who illegally scoop them up from the water on the Great Barrier Reef.

Sea Turtles

On the Great Barrier Reef we are blessed with six of the seven Sea Turtle species found on this planet.

During the months of November to March the turtles lay eggs on the islands and beaches that line the coastline.

Visitors to the reef commonly see sea turtles on the regular day trips from Cairns, Port Douglas and the Whitsunday Islands and they get very excited when they come across the one’s that are so used to tourists that they swim alongside you.


The movie “Finding Nemo” made the Clownfish very famous when Nemo and his dad Marlin were made the lead characters in the film about the Great Barrier Reef.

Clownfish are very cute as you see them popping in and out of their safe haven amongst the stinging tentacles of the sea anemone of which they have a close symbiotic relationship that protects each other from predators and parasites.

There are around thirty species of clownfish recognised and you will find them all over the Great Barrier Reef on your dive and snorkel tours.

Maori Wrasse

Humphead Maori Wrasse are also the playful puppies of the Great Barrier Reef just like the Giant Potato Cod fish.

They too can calculate the arrival and departure of boats and seek constant attention from the divers and snorkelers all day long.

These wonderful good looking fish can grow up to 2.3m and weigh 190kg.

Their growth goes thru three life phases – the juvenile stage where they are lighter in colour, the initial phase in which you have a variety of males and females as they once again change colour with growth, and the terminal phase which only has males.

This sex transformation occurs when a dominant male dies and the largest of the females in the group or family changes sex to then take its place.

Maori Wrasse are a no take species of fish on the Great Barrier Reef.

Manta Rays

Manta Rays are the gentle giants of the sea always conducting underwater ballet as they swim along the oceans currents and mingle with other Manta Rays at the cleaning stations on the reef.  

These wonderful animals can grow up to 7mt from wing to tip and have no stinging barb such as the shy stingrays and they have the largest brain to weight ratio of any living fish.

Each Manta Ray is individually identified by it’s underbelly markings and researchers photograph and catalogue each one so they can learn more about these marine animals. 

Manta Rays although present all year round on the reef, they are more commonly seen during the winter months of May, June, and July in great numbers.

Giant Clams

You may be wondering why the Giant Clams made the Great Eight list of amazing marine life on the Great Barrier Reef so we shall enlighten you here below.

These Giant Clam have a unique way of reproduction called broadcast spawning.

As the clams cannot move they have the ability to produce both eggs and sperm and a transmitter substance called spawning induced substance helps synchronize the release of sperm and eggs with other clams at the same time ensuring fertilisation.

Clams come in all shapes and sizes and wonderful colours and can be seen all over the Great Barrier Reef all year round.

Giant Clams can measure as much as 120cm across and weigh more than 200 kilograms.

They live in flat coral sand or broken coral beds in various depths of water.

Many years ago you may have heard the old seaman’s tales of how these Giant Clams claimed the lives of many divers who dared to place their hands or feet into the mantle of the clam to have it close like lightening and as hard as a vice so they could not escape.

Whilst one or two of these fanciful tales may be true these Giant Clams are not aggressive they simply close up if they feel a predator is about to attack them.

The valves of the clam close too slowly pose a serious threat for entrapment but it is always advised like with all other attractions on the Great Barrier Reef look with your eyes not your hands.


Whilst the ocean is the home of sharks you will find different species live and travel to different parts of the ocean on an annual basis.

The more aggressive sharks such as the Great White can be more commonly found in the southern colder waters and not normally in the warmer waters of the Great Barrier Reef, where you will see white tip and black tip reef sharks every day when you are out on a snorkel and dive trip.

Most of the time you will see the shark pups swimming amongst the corals looking for meal time opportunities.

These white tip and black tip sharks are harmless and very shy when they come across humans swimming off as fast as they can.

The reef has small bottom dwelling sharks like the Wobbegongs and Tiger and Hammer heads more likely to be seen out in the deeper dive locations on the northern Great Barrier Reef.

If you are a shark diving enthusiast there are a number of private charter shark dive tours, shared charter shark diving trips and feeding sharks dive trips that you can book here.        

For more information about seeing the Great Eight marine life on the Great Barrier Reef read here and to book your Great Barrier Reef holiday tours and attractions see here.  

If you can't find what you are after, don't hesitate to give us a call on 1300 231 118.

Christina James

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