Eastern blue groper
Meet another famously blue but completely different Sydney fish, and learn how its colour, size and behaviour change through life.
Read the eastern blue groper guide →Sydney marine life
Eastern Blue Devil Fish: Sydney’s Secretive Reef Fish
Meet Paraplesiops bleekeri—a striking but naturally uncommon fish that shelters beneath rocky ledges and is protected throughout NSW.
Protected fish in NSWThe Eastern Blue Devil Fish is one of the most memorable fish a Sydney diver can encounter. Its electric-blue markings, pale body bands and yellow fins are unmistakable, but the fish itself is shy. Look carefully from outside its shelter, give it an open escape route and never touch, chase, feed or corner it.
Paraplesiops bleekeriScientific name
Bleeker’s devilfishAlternative common name
3–30 metresCommonly reported; verified to 51 m
Up to 40 cmMaximum reported length
Rocky shelterCaves, crevices and ledges
Protected in NSWDo not take or possess
Identification
How to recognise an Eastern Blue Devil Fish
Adults combine a bold banded body with vivid blue and yellow details. Those colours can appear especially intense when a dive light reaches a fish inside a shaded ledge.
The accepted scientific name is Paraplesiops bleekeri. “Bleeker’s devilfish” is an alternative common name; the fish is not an eastern blue groper and the two should not be confused.
Juveniles are rarely observed and are less colourful than adults. NSW Fisheries describes them as dusky brown with subdued bands, while blue spots on the head and gill covers and blue fin edges can remain visible.
Blue-and-pale body bands form the adult fish’s most obvious pattern.
Fine blue spots cover the head, with blue colour also running through the dorsal and anal fins.
Yellow pectoral and tail fins contrast strongly with the blue markings and pale bands.
Elongated pelvic, dorsal and anal fins overlap when spread, making the fish look larger.
Not a blue groper: the similarly named eastern blue groper is a different species with a different body shape and colour pattern. The shared word “blue” is the main similarity.
Habitat and range
Where does the Eastern Blue Devil Fish live?
This Australian endemic occurs from southern Queensland along the NSW coast to southern New South Wales. Authoritative sources differ slightly on the precise southern endpoint, so the broader range is the safer description.
Under cover
A fish of caves, crevices and ledges
Eastern blue devil fish are benthic reef inhabitants. During the day they usually shelter alone inside rocky caves, in crevices or beneath overhangs on estuarine, inshore and offshore reefs.
Sydney context
Present locally, but never guaranteed
The species occurs around Sydney’s rocky coast and saline estuarine habitat within its wider range. NSW Fisheries commonly reports it between about 3 and 30 metres, while a peer-reviewed observation has verified the species at 51 metres. Natural rarity, sheltering behaviour and conditions make every sighting a matter of chance.
Protect the shelter as well as the fish. Do not enter a tight recess, move rocks or publish a precise den location. Explore the variety of Sydney dive sites, then use the day’s dive conditions and your guide’s briefing to choose an appropriate dive.
Behaviour and life cycle
Secretive by day, more active after dark
Reliable information about this naturally uncommon fish remains limited. The points below reflect the current NSW Fisheries species profile rather than filling those gaps with assumptions.
Daily rhythm
Shelter and activity
Adults are usually solitary and occupy caves, crevices or ledges during daylight. NSW Fisheries reports that they are most active at night.
Feeding
Diet is poorly known
Little has been documented about their diet. Brittle stars are one confirmed food item, but it would be misleading to describe a complete diet from that observation.
Territory
Male defence is inferred
Males are thought to defend a cave or overhang to attract a mate and drive away other males. The cautious wording matters because this behaviour is not fully documented.
Breeding: NSW Fisheries reports a season from October to March. Groups of eggs are attached beneath a cave or ledge until they hatch. The free-swimming larvae are about 4 mm long at hatching and settle around reef habitat at roughly 10 mm. Reproductive output beyond these observations is not well documented.
Protected in NSW
Why is the Eastern Blue Devil Fish protected?
NSW Fisheries identifies natural rarity, low abundance and collection for the marine-aquarium trade as the key reasons for protection. Safeguarding rocky estuarine and offshore reef habitat is also central to conserving breeding populations.
Protection means leave the fish where it lives
The current Fisheries Management (General) Regulation 2019 lists Paraplesiops bleekeri as a protected fish and declares its possession prohibited absolutely. Section 19 of the NSW Fisheries Management Act 1994 makes taking or possessing protected fish an offence.
If you witness suspected illegal collection or possession, do not put yourself at risk. Use the NSW Fisheries illegal-activity reporting service.
Responsible encounters
How to observe an Eastern Blue Devil Fish without crowding it
The best encounter is one that leaves the fish in control of the distance. Settle outside its shelter, keep the exit clear and let the animal decide whether it remains visible.
Pause outside
Do not push into a cave or recess for a closer look. Stop where the fish still has room to retreat or leave.
Hold neutral buoyancy
Keep fins, gauges and hoses away from the reef so the shelter and the life growing around it remain undamaged.
Keep the exit open
Never position divers on every side of the fish or block the obvious route out of its ledge.
Use light gently
Avoid prolonged intense torch or focus-light exposure. Take the photograph, reduce the beam and move on.
Do not interact
Never touch, chase, feed, prod or attempt to draw the fish from cover for a better view.
Leave when behaviour changes
If the fish repeatedly retreats or appears boxed in, increase the distance and end the encounter.
Wildlife encounters are never guaranteed. Choose a dive for the site, conditions and experience itself—not on a promise of seeing a particular fish. Learn more about diving in Sydney and browse current Sydney marine-life dives.
Keep exploring
More of Sydney’s distinctive marine life
Continue with local species guides that make Sydney diving distinctive in every season.
Straight answers
Eastern Blue Devil Fish FAQs
Is the Eastern Blue Devil Fish protected in NSW?
Yes. The current NSW Regulation lists it as a protected fish and declares its possession prohibited absolutely. Section 19 of the Fisheries Management Act 1994 makes taking or possessing protected fish an offence, with substantial penalties.
Where do Eastern Blue Devil Fish live?
They shelter in caves, crevices and beneath ledges on estuarine, inshore and offshore rocky reefs. They occur from southern Queensland to southern New South Wales. NSW Fisheries commonly reports a depth range of about 3 to 30 metres, although the species has been verified at 51 metres.
How do you identify an adult Eastern Blue Devil Fish?
Look for pale and blue body bands, fine blue spots on the head, blue dorsal and anal fins, yellow pectoral and tail fins, and elongated rear fins that overlap when spread.
How large can an Eastern Blue Devil Fish grow?
Both NSW Fisheries and the Australian Museum report a maximum length of about 40 cm.
Is an Eastern Blue Devil Fish the same as an eastern blue groper?
No. They are different species with different body shapes, markings and ecology. The common-name similarity can cause confusion, but the Eastern Blue Devil Fish is the banded fish with yellow fins shown on this page.
Can a Sydney dive guarantee an Eastern Blue Devil Fish sighting?
No. The species is naturally uncommon and usually remains close to shelter. Sightings depend on site, conditions, season, animal behaviour and chance, so no responsible operator should guarantee an encounter.
Sources checked for this update
Biology was checked against NSW Fisheries, the Australian Museum, Fishes of Australia and peer-reviewed research. Protected status and penalties were checked against the in-force NSW Act and Regulation. Scientific knowledge and laws can change, so the linked primary sources remain the final reference.
Explore with care
Discover Sydney’s marine life responsibly
Choose a dive suited to your certification, recent experience and the day’s conditions. The best local dives respect wildlife, protect reef habitat and leave every animal free to decide the encounter.
Information reviewed and fact-checked 25 August 2026. Wildlife sightings are natural and never guaranteed.
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