Explore SA’s wonderful world of reef fish

It’s not just the Great Barrier Reef that’s home to amazing sea creatures – South Australia has its fair share too.

Marine life in South Australia is actually more varied than the Great Barrier Reef and many species found here can’t be seen anywhere else in the world.

In the waters around Adelaide alone there are certainly some interesting fish to be found – some with striking colours, some with unusual names that sound like evening wear, and others that grow old enough to well and truly be great-great-grandparents.

Here are five picks from Marine Ecologist Janine Baker’s reef fish guide for you to look out for on your next underwater adventure:

1. Harlequin fish (Othos dentex)

This colourful fish has been spotted all the way from Encounter Bay in Adelaide’s south, to the Great Australian Bight in the state’s west, as well as across in Western Australia where they’re much more common.boa

They can live for longer than 40 years and grow to about 76 centimetres. Individuals can be identified by their unique patterns of spots. This has allowed researchers to monitor their movements and learn that these fish seem to stay on, or return regularly to, the same reefs that they’ve always lived on.

Most likely to be spotted more than 10 metres below the surface, this carnivorous species has a special tactic for catching its dinner – waiting for it to pass by, sometimes hiding from it first, and jumping out to attack it.

The harlequin fish has also been credited with helping to create SA’s marine sanctuaries – so it’s safe to say it’s a special fish.

 Dr Bryars and Harlequin fish
Marine Biologist Simon Bryars with a harlequin fish about to be released alive as part of a marine parks fish tracking study

2. Southern blue devil (Paraplesiops meleagris)

These vibrant fish can be found between 5 m and 45 m – or sometimes more – below the water’s surface. They mostly live in caves or around ledges, which are rocky ridges found underwater, but have also been found near shipwrecks and artificial reefs.

Like harlequin fish, individual southern blue devils can be identified by their different blue markings. These territorial and curious fish seem to spend much of their lives within a small area of reef, and can get to about 36 cm in size. On their menu? Crabs and bony fish.

When it comes to reproducing, males protect the eggs, watching over them until they hatch. You’re likely to find these fish in Encounter Bay, part of Encounter Marine Park, as well as in the Aldinga Reef Sanctuary Zone.

Blue Devil
(Image courtesy of Anthony King, Flinders University Underwater Club)

3. Western blue groper (Achoerodus gouldii)

Western blue gropers live up to 70 years old and can reach 160 cm – but it takes them 15 years just to reach 60 cm. They also change sex as they age.

The age of the fish can influence where and how deep you can find them but generally they can be found anywhere from 1 m to 80 m underwater, usually in caves or rocky reefs. And they’re actually protected species in Gulf St Vincent and Spencer Gulf.

Western blue groper

4. Banded morwong (Cheilodactylus spectabilis)

If you thought that 70 was old for a fish, then you’ll be surprised to discover that the banded morwong can live to 95 years old.

Found between south-east SA and the Great Australian Bight, as well as other locations around Australia and New Zealand, this species likes shallow coastal reefs and eats things such as sea urchins and small crabs.

Growing to a maximum of 100 cm, but more often only 75 cm, the number of stripes on the banded morwong is surprisingly specific – it’s either seven or eight. 

Banded Morwong
(Image courtesy of Erik Schlögl, © Australian Museum)

5. Blue-tailed leatherjacket (Eubalichthys cyanoura)

With a name that sounds like a jacket you pull out for a Saturday night on the town, it’s only fitting that the blue-tailed leatherjacket looks so cool. This fish is one of many different leatherjackets that can be found in SA’s waters – a number of which also sound like awesome outfits: brown-striped, horseshoe and six-spined. 

If you were going to spot this species it would be between 3 m and 20 m underwater, but it’s not common to find as it’s a rather timid fish. The blue-tailed leatherjacket grows to approximately 42 cm and will look different depending on its size, age and sex.

Bluetail leatherjacket
(Image courtesy of David Muirhead, © Australian Museum)

There’s a good chance you’ll need to go diving to discover these amazing fish, so why not hook yourself up with a tour or go snorkelling with a professional instructor? And if all this talk of fish has got you craving more underwater adventures, look at the activities and events on offer around the state as part of the Immerse Yourself summer holiday sessions.

You can also get in the know about other colourful coastal and marine creatures from the comfort of dry land by checking out the Natural Resources Adelaide and Mount Lofty Ranges website.


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