Welcome to the Marine Mili series, a regular column about all things marine! During this series I aim to inspire people to want to protect our oceans and all the marine life that call our oceans home. Hopefully after reading each column, you would have learnt something new including what we can do to help protect and preserve our oceans. You can follow me and my journey on my Instagram page: _marine_mili.

Meet the Southern Blue Devil fish, a beautiful and vibrant local species of fish that is found along the southern coast of Australia.

The Southern Blue Devil is known for its vibrant colours and also for their large pelvic and anal fins. This species is found in caves and rocky reef ledges and these slow-moving fish have a quite long lifespan, reaching up to 60 years.

Southern Blue Devil fish are usually found in breeding pairs where they hang out in safe places like caves. The males stay in the caves and guard their eggs until it is time for them to hatch. Often, pairs will find a certain cave or rocky site and use it like their home. Unlike other fish who travel around, the Southern Blue Devil fish stay at their caves for extended periods of time and return to them.

Individuals can be identified by the markings on their gill cover which is unique to each fish, allowing scientists to monitor individual fish closely.

The species is a diver’s favourite as they are very slow-moving and often are comfortable approaching divers. They are also amazing to photograph, making them a highlight species for many underwater photographers.

I personally have only encountered a Southern Blue Devil fish once, and it was my first boat dive. They are very special creatures and what an experience it was to get to see a pair of them in real life.