Weedy, Leafy and Ruby Seadragons: What’s the Difference?
Peter Letts Mar 08, 2025
Australia’s true ocean dragons
Australia’s Three Seadragon Species: Weedy, Leafy and Ruby
A scientifically checked comparison of three Australian endemic fishes—and the very different habitats, appearances and lives hidden behind one extraordinary name.
There are three recognised seadragon species: the common or weedy seadragon, the leafy seadragon and the ruby seadragon. All are native only to Australia, but only the common/weedy species has an established natural population in Sydney.
Seadragon species at a glance
Weedy vs leafy vs ruby: the essential differences
These are not three names for the same animal. They are three distinct species in two genera, separated by genetics, geography, habitat and unmistakable physical features. “Common seadragon” is the accepted standard name for the fish Sydney divers usually call the “weedy seadragon”; both names refer to Phyllopteryx taeniolatus.
| Feature | Common / weedy | Leafy | Ruby |
|---|---|---|---|
| Scientific name | Phyllopteryx taeniolatus | Phycodurus eques | Phyllopteryx dewysea |
| Fastest visual clue | Smaller leaf-like appendages, blue bars and intricate spots | Large, elaborate, kelp-like appendages over the body | Ruby-red body with no leafy dermal appendages |
| Maximum published length | About 45 cm | About 35 cm | About 26 cm |
| Established range | NSW, Victoria, Tasmania, South Australia and Western Australia | South Australia and Western Australia | Known from southern Western Australia |
| Typical habitat | Kelp and other macroalgae, rocky reef, seagrass and adjacent sand | Macroalgae, Posidonia seagrass, reef and sand | Observed at one deep site over mixed sand and reef with sponges, hydroids and bryozoans; habitat preferences remain unknown |
| Documented depth | Often shallow coastal habitat; recorded to about 50 m | Usually shallow; published records extend to about 50 m | Specimens and live records from about 51–72 m |
| Found naturally in Sydney? | Yes | No established population | No |
| Current IUCN status | Vulnerable | Least Concern | Data Deficient |
Conservation categories are global IUCN Red List assessments, not a measure of how easy a species is to find at one dive site. Statuses checked 12 August 2026.
Family resemblance
What makes a seadragon a seadragon?
Seadragons are ray-finned fishes in the family Syngnathidae, alongside seahorses and pipefishes. They are not a type of seahorse. Their long bodies are encased in ring-like bony plates, their jaws are fused into a narrow tube-shaped snout, and the male carries developing eggs beneath his tail.
They breathe through gills and swim with small fins. The decorative appendages are skin structures, not the fins that power movement.
The toothless tubular snout rapidly draws tiny prey into the mouth, much like a precision pipette.
Colour, pattern, body shape and a slow swaying motion help common and leafy seadragons disappear among marine plants.
Eggs develop on an exposed specialised brood patch beneath the tail—not inside a sealed seahorse-style pouch.
Species 1 · The Sydney seadragon
Common or weedy seadragon
Phyllopteryx taeniolatus has the widest distribution of the three species. Its established range follows temperate southern Australia from New South Wales through Victoria, Tasmania and South Australia to Western Australia. It is the only seadragon with a resident natural population around Sydney.
Adults are usually brown, orange or reddish, patterned with fine spots and striking blue bars. Their leaf-like appendages are much smaller and simpler than those of a leafy seadragon. They can reach about 45 cm total length, making this the longest of the three species.
Common seadragons feed heavily on mysid shrimp and other small crustaceans. Around Botany Bay, research shows they use a balance of kelp cover for camouflage and nearby open habitat where mysids gather. That is why a sensible search includes kelp-covered reef, kelp edges and adjacent sand—not sand alone and certainly not an instruction to ignore the kelp.
- Alternative name: weedy seadragon, especially familiar on Australia’s east coast.
- Sydney status: resident in suitable habitat throughout the year; individual sightings remain unpredictable.
- Conservation: reassessed as Vulnerable on the IUCN Red List in 2024.
Species 2 · The master of kelp mimicry
Leafy seadragon
Phycodurus eques is the only living member of its genus. It carries long, elaborate dermal appendages across its head, body and tail, creating the most extravagant seaweed disguise of any seadragon. Those “leaves” are not propulsion fins. A small dorsal fin and pectoral fins provide movement while the appendages break up the animal’s outline.
Leafy seadragons occur in established populations in South Australia and Western Australia. Reports from Victoria and Tasmania are rare or unverified and are not evidence of established populations. They do not naturally live in Sydney.
They reach about 35 cm and are commonly associated with macroalgae, Posidonia seagrass, reef and nearby sand. Their colours range through gold, greenish yellow and brown; animals from deeper habitat can appear darker or redder. This natural variation should not be simplified into a claim that every seadragon can rapidly change colour on demand.
- Diet: small crustaceans. Wild diet data are limited; recorded prey includes isopods, prawns and leptostracans, while captive animals eat mysids.
- Maximum published length: about 35 cm.
- Conservation: Least Concern globally, but fully protected and still dependent on healthy habitat.
Species 3 · The deep-water discovery
Ruby seadragon
Phyllopteryx dewysea overturned a century and a half of assumptions. Scientists formally described it in 2015 after DNA and anatomical work on museum specimens collected in 1919, 1956 and 2007 revealed a third species. Researchers then filmed living ruby seadragons by remotely operated vehicle in 2016, publishing the first live records in 2017.
The ruby’s name is literal: it is deep red with pink vertical bars and pale facial markings. But the old article had its most important feature backwards. Ruby seadragons lack the leaf-like dermal appendages found on common and leafy seadragons. Red light is rapidly absorbed in deep water, so a red animal can appear dark and inconspicuous in its low-light habitat.
Where it lives
Known only from southern Western Australia. Specimens and live observations come from roughly 51–72 m—mostly beyond ordinary recreational scuba limits.
How it differs
About 26 cm maximum, red rather than kelp-coloured, without leafy appendages, and with a tail that appears likely to be prehensile.
What remains unknown
Its diet has not been established. Researchers observed bottom-oriented feeding strikes but could not identify the prey. Its range and population are also poorly known.
Why there is no ruby photograph here: none of the supplied Abyss images depicts a verified ruby seadragon. Rather than mislabel a common or leafy animal, this guide links to the peer-reviewed first live records and images.
Identification in seconds
The quickest way to tell the three apart
Look for a long reddish-brown or orange body, intricate spots, vertical blue bars and a modest number of simple leaf-like appendages.
The abundant, long, lobed appendages are unmistakable. This is a South Australian and Western Australian species, not Sydney’s local fish.
The absence of dermal appendages is diagnostic. Habitat also matters: known live observations are from deep southern Western Australian water.
One country, three different ranges
Where seadragons live in Australia
All three recognised species are endemic to Australia’s temperate Great Southern Reef, but they are not spread evenly around the continent. The common/weedy seadragon has the broadest range; the leafy is concentrated farther west and south; the ruby is known only from deep sites in southern Western Australia.
This is a state-level summary of established ranges, not a promise that every part of a state contains seadragons. Ruby distribution is especially uncertain because so few living animals have been observed.
How they live
Feeding, swimming and disappearing in plain sight
Mysid shrimp can make up more than 80% of the diet in studied populations, alongside other tiny crustaceans.
Small crustaceans are the main prey. Evidence from wild animals is much more limited than many simplified fact sheets imply.
Unknown. Feeding strikes have been filmed, but researchers could not identify what the animals captured.
Small pectoral and dorsal fins propel and steer the body. Swaying with surge helps common and leafy species maintain the illusion of drifting algae.
Camouflage does two jobs: it makes a seadragon harder for predators to recognise, and it lets the fish approach small mobile prey without advertising itself. The common and leafy species combine pattern, colour and appendages with vegetated habitat. The ruby appears to use red colour as camouflage in deep, low-light water where leafy appendages may create more drag than benefit.
Male brood care—correctly explained
How male seadragons carry the eggs
The old version reversed the process. Seadragon eggs do not remain inside the female until hatching, and the male does not transfer a spermatophore to her. After courtship, the female transfers eggs from her cloaca to a specialised exposed brood patch beneath the male’s tail. Fertilisation occurs as the eggs are placed, and the male carries them until fully formed young hatch.
Seadragons do not have the enclosed brood pouch familiar from many seahorses. The eggs remain visibly attached to the tail. Published incubation periods vary by species and setting, but a broad synthesis places incubation at about 30–42 days.
Brood size is not one universal number. A Sydney common/weedy male may carry around 250 eggs and can have two broods in a season; leafy accounts can reach roughly 250–300; the ruby holotype carried only several dozen developing young. Hatchlings are independent soon after emerging and lack a long dispersive larval stage.
The pair coordinate through repeated swimming displays and body movements.
The female places eggs onto the specialised patch beneath the male’s tail.
The male protects and supports the attached developing embryos.
Miniature, independent young emerge directly into their local habitat.
Status is not the whole story
Conservation status and threats by species
All three seadragons are protected in Australian waters, but legal protection from collection does not protect a kelp forest from heat, a seagrass meadow from degradation or a local population from an extreme storm. Limited movement, low reproductive output, strong site fidelity and little larval dispersal can make recovery from local loss slow.
The IUCN reassessed this species as Vulnerable in 2024. Important pressures include loss and degradation of kelp and seagrass, warming and marine heatwaves, urban coastal impacts and severe storms.
Least Concern does not mean “no concern.” Its smaller established range, relatively few monitored populations and reliance on temperate vegetated habitat still justify protection and better long-term data.
Data Deficient is not a finding that the species is safe. Too little is known about its abundance, full distribution, ecology and threats to estimate extinction risk reliably.
A 2025 scientific review reports the common and leafy species under their earlier Least Concern assessments. The current IUCN record now shows the common/weedy seadragon as Vulnerable following an assessment dated 5 July 2024. This page uses the current IUCN record for each species.
From photograph to evidence
Help researchers recognise individual seadragons
Adult common and leafy seadragons carry stable natural markings that can act like fingerprints. SeadragonSearch combines diver photographs, citizen science and pattern-matching tools to record repeat sightings and build better population knowledge across southern Australia.
Make the encounter useful—and responsible
- Never touch, handle, chase, feed, surround or reposition a seadragon.
- Maintain neutral buoyancy and keep fins, gauges and camera equipment clear of habitat.
- Leave the animal an open direction of travel and back away if it repeatedly evades divers.
- Give brooding males extra room and avoid positioning beneath the exposed eggs.
- Limit flash to three or four spaced shots per encounter, and use bright video lights cautiously.
- Keep the original image and record the date and location accurately.
Learn more about how divers contribute to seadragon citizen science.
The species Sydney divers can meet
Which seadragon lives in Sydney?
The common or weedy seadragon is Sydney’s seadragon. Leafy seadragons have established populations in South Australia and Western Australia; ruby seadragons are known only from deep southern Western Australian sites. Neither is a natural Sydney encounter.
For local dive planning, species identification, seasonality, responsible photography and every Abyss encounter option, continue to the main Sydney weedy seadragon dive hub. Wild sightings are never guaranteed, and the safest suitable site depends on current conditions and diver experience.
The Steps at Kurnell
A well-known Botany Bay shore-dive site with kelp, sand and reef habitat used by common/weedy seadragons.
Dragon’s Lair
A specialist Sydney boat-dive site known for the chance to encounter common/weedy seadragons.
Marine Marvels
A marine-biologist-led guided dive focused on Sydney’s smaller, unusual and easily overlooked marine life.
Choose your own date
Certified divers can arrange a private guide for a suitable Sydney shore dive planned around conditions and experience.
Frequently asked questions
Seadragon species FAQs
How many seadragon species are there?
There are three recognised true seadragon species: the common or weedy seadragon (Phyllopteryx taeniolatus), the leafy seadragon (Phycodurus eques) and the ruby seadragon (Phyllopteryx dewysea). All three are endemic to Australia.
Are leafy and weedy seadragons the same species?
No. The common or weedy seadragon is Phyllopteryx taeniolatus; the leafy seadragon is Phycodurus eques. Leafies have much larger and more elaborate appendages and a more restricted established range in South Australia and Western Australia.
Which seadragon species lives in Sydney?
The common or weedy seadragon is the only seadragon with an established natural population in Sydney. For Sydney locations, responsible viewing guidance and guided options, visit the Sydney weedy seadragon dive hub.
How is the ruby seadragon different?
The ruby seadragon is deep red, lacks the leafy dermal appendages of the other two species, grows to about 26 cm and appears to have a prehensile tail. It is known from deep southern Western Australian habitat, with specimens and live records from roughly 51–72 m.
Are seadragons seahorses?
No. Seadragons and seahorses are different groups of fishes within the same family, Syngnathidae. They share features such as tube-shaped snouts and male brood care, but differ in body form, swimming posture, appendages and tail function.
Do male seadragons carry the eggs?
Yes. The female transfers eggs to a specialised exposed brood patch beneath the male’s tail. The male incubates the attached embryos until fully formed young hatch. Unlike many seahorses, seadragons do not carry the eggs inside a sealed brood pouch.
Can seadragons change colour?
Colour varies among and within species and can be influenced by habitat, depth, diet, age and condition. The size and shape of dermal appendages also vary, and leafy seadragons may adjust colour over time. It is misleading to claim that every seadragon rapidly changes colour on demand. Ruby seadragons instead appear to rely on naturally red colour for camouflage in deep, low-light water.
Scientific and conservation sources
- 2025 scientific review of all three seadragon species
- Fishes of Australia: Common Seadragon
- Fishes of Australia: Leafy Seadragon
- Fishes of Australia: Ruby Seadragon
- 2015 original description of the ruby seadragon
- 2017 first live records of the ruby seadragon
- IUCN Red List: Common/Weedy Seadragon
- IUCN Red List: Leafy Seadragon
- IUCN Red List: Ruby Seadragon
- Research on common seadragon habitat and prey use
- SeadragonSearch code of conduct
Written by Peter Letts for Abyss Scuba Diving. Scientific information and conservation status checked 12 August 2026. Taxonomy, ranges and assessments can change; the linked scientific and conservation records take precedence.
Want to meet Sydney’s seadragon in the wild?
The comparison ends here; the local adventure starts on Abyss’s dedicated Sydney hub, where you can learn how to spot a common/weedy seadragon and choose the right guided pathway.
Trusted by Sydney divers