Bookmark and Share

Buddy-up with a blue devil

There are few moments more thrilling for Victorian divers than when a Blue Devil Fish looms into the view.

Its polka-dot blue body, long, trailing fins and startling yellow eyes make the Blue Devil Fish a favourite with divers from Western Australia to Victoria.

And yet we know very little about this intriguing fish.

That's why we've launched Buddy-up with a Blue Devil, a new Reef Watch program to help marine researchers learn more about our underwater devils - where they live, how long they live for, their mating habits and much, much more!


What we know

Buddy-up with a Blue Devil - online sighting report

Blue Devil Fish are a brilliantly coloured deep blue, making them one of the most entrancing sights for divers on Victorian rocky reefs. They have many small, evenly scattered, bright blue spots, and sometimes faint dark bars on their side.

Recent scientific studies using digital cameras to photograph markings on the sides of their gills indicate the Blue Devil Fish rarely leaves the rocky reefs, caves and crevices it calls home.

Described as 'generalist carnivores', Blue Devil Fish eat other bony fish and bottom-dwelling crustaceans. They are known to live for up to 59 years.


What we want to know

By collecting information on Blue Devil Fish we will be able to provide valuable baseline information to the scientific community on the fish's population, distribution and natural history (breeding times, egg laying). We will also be able to monitor any changes to their habitat over time.

We need good quality photos of Blue Devil Fish, ideally one photo of each side of the head.


Naming your devil

The first person to submit a photo of a particular Blue Devil Fish to Reef Watch wins naming rights and becomes that devil's 'Blue Devil Buddy'.

You can have as many buddies as you can manage - you just have to be the first person to send in the image of the fish. We'll put the photos on Facebook so our divers and supporters can check out your new blue friend.

Techie stuff: the photo is yours, of course, but by sending us the image you agree that it can be reproduced by Reef Watch or associated parties for the purposes of the project or VNPA activities.


Devil in the details

Size: Blue devils can grow to around 36cm in length. The heaviest recorded specimen was 1.13 kg. It is thought that devil fish are mature at around 15cm in length. This is when their individual 'spot' marking is the most stable.

Habitat: Blue devils are territorial fish that occur in the vicinity of rocky reefs, often in caves and crevices, and under ledges and overhangs, usually between 5m and 45 m deep.

Behaviour: The species is rarely seen in large numbers - they tend to be solitary creatures or mate for life. The menfolk are thought to guard the eggs laid within rocky lairs. They can exhibit aggressive behaviours such as flaring their gill covers and extending their fins.

Distribution: Houtman Abrolhos, WA to Port Philip Bay, Victoria.

Threats: Blue devils are of conservation concern because they are site-attached (tend to make specific rocky sites their home), making them vulnerable to localised depletion through fishing or habitat degradation.


How to report your blue devil sighting

To make it easy for you to record sightings of your Blue Devil we've set up a simple reporting page.

When filing your report please make sure you fill in every field. It's also vital that you email images of both the left and right cheeks of your Blue Devil. Without those images the rest of your sighting data is invalid.

Report your blue devil sighting