Seadragons: Australia's Endemic Icons

There is no other fish like a seadragon, and there is nowhere else to see one. Both species are endemic to the temperate reefs of southern Australia, which means the diving you can do at Rye Pier or Rapid Bay is diving that literally cannot be done anywhere else on the planet. For a country that markets its tropical reef relentlessly, the seadragon is the animal that should be on the poster.

Two species, and a third almost nobody sees

The common seadragon (*Phyllopteryx taeniolatus*), still widely called the weedy seadragon, is the one most Australian divers meet. It runs to about 45cm, is reddish to purple-brown with yellow spotting and vivid blue-white bars, and carries short leaf-like appendages that are decorative rather than genuinely concealing. It ranges across the southern coast from central New South Wales around to Western Australia, including Tasmania.

The leafy seadragon (*Phycodurus eques*) is the spectacular one. Its appendages are elaborate golden-olive fronds that make it almost indistinguishable from drifting kelp, and its range is much tighter: South Australia and southern Western Australia. If you want to see a leafy, you go to South Australia. There is no east coast option.

There is also a third species. The ruby seadragon (*Phyllopteryx dewysea*) was only described in 2015, is deep red, and lives in deeper water off Western Australia. Essentially no recreational diver has seen one in the wild, which is a useful reminder of how much of temperate Australia remains poorly explored.

The males carry the eggs

Seadragons belong to the family Syngnathidae, alongside seahorses and pipefish, and they share the family's most famous trait: male pregnancy.

The female produces the eggs and transfers them to the male, who carries them on a brood patch on the underside of his tail. A common seadragon male carries roughly 120 eggs, embedded in a spongy patch of tissue that supplies them with oxygen. He carries them for around four to six weeks before the young hatch out fully formed as miniature versions of the adults, receiving no further parental care.

A brooding male is worth recognising, and worth leaving alone. If you see the distinctive pinkish-purple cluster of eggs under a tail, keep your distance and keep your strobe off.

Seadragons have no teeth and no stomach. They feed by drawing tiny crustaceans, mostly mysid shrimp, through that long snout with a sharp pipette-like suction, and because they cannot store food they have to feed more or less continuously. A seadragon hovering over seagrass is not resting, it is working.

Where to see them

Victoria is the most reliable place in the country for common seadragons. Flinders Pier is the standout, one of the best seadragon dives in Australia, in shallow water among the seagrass. Blairgowrie Pier and Rye Pier are both dependable, and all three are easy shore dives.

South Australia is where you go for leafies, although the 2025 algal bloom has made them far scarcer (see below). Rapid Bay Jetty on the Fleurieu Peninsula is the famous one, but the old jetty the leafies lived under has been a prohibited area since June 2025; you can still dive from the new jetty and in the seagrass outside the boundary buoys. In March 2026 the Scuba Divers Federation of South Australia (SDFSA) reported strong numbers of common seadragons and the occasional leafy there and at Second Valley, just along the coast.

Sydney has a genuine population that surprises visitors. Kurnell Monument, The Leap and Bare Island all hold common seadragons, but Bare Island is closed to visitors from 24 August 2026 until late 2027 while NSW National Parks repairs its bridge.

Tasmania puts them in colder, clearer water at sites like Fortescue Bay and Tinderbox Marine Reserve.

The 2025 die-off in South Australia

In 2025 South Australia recorded the largest mass mortality of leafy and common seadragons ever documented. A harmful algal bloom, dominated by the dinoflagellate *Karenia mikimotoi*, was identified off the Fleurieu Peninsula in March 2025 and spread through Gulf St Vincent and beyond, and by September the IUCN's seahorse, pipefish and seadragon specialist group was reporting that thousands of seadragons had died. They were among the first fish found washed up. Their small gill pores clog easily with the algae, and unlike fast-swimming fish they cannot escape a dense bloom.

By September 2025 citizen scientists had logged thousands of dead common seadragons in almost 400 iNaturalist records, and hundreds of dead leafies in 63 more, and the specialist group says those figures understate the real toll. The worst-hit areas included western and south-western Gulf St Vincent, southern Yorke Peninsula, northern Kangaroo Island and the Encounter Bay coast. Most of the deaths came in autumn and winter, just before the breeding season, so the young those adults would have produced were lost as well.

The effect at the best-known site is stark. In March 2026 Divers for Climate told InDaily that Rapid Bay used to have about 45 known resident leafies and that local divers were now lucky to find one or two, even as common seadragons turned up there in unusual numbers. If you dive in South Australia, your photos help: SeadragonSearch uses divers' underwater images to track wild seadragons, matching individuals by their face and body patterns, and the SDFSA has urged divers to contribute so the bloom's impact on both species can be measured.

Finding one

Seadragons are hard to see and easy to swim past, and almost every diver's first sighting is pointed out by somebody else.

Look for the wrong kind of movement. A seadragon drifting in surge moves with the water, which is the entire point of the camouflage, but it moves slightly out of phase with the actual weed around it. That mismatch is what your eye eventually learns. Search seagrass margins and kelp edges in 3 to 12 metres rather than open reef, work slowly, and scan at a distance rather than sticking your mask into the weed. They also tend to be found in the same patches year after year, so local knowledge is worth more than searching effort.

Diving with them responsibly

Both species are protected in Australian waters, and taking one is illegal.

The rules that matter in the water are simple. Do not touch, ever, and do not attempt to reposition an animal for a photograph. Do not chase: a seadragon that turns away and starts swimming has been pushed too hard, and it burns energy an animal that cannot store food can ill afford. Keep clear of brooding males entirely. Watch your fins around seagrass, since the habitat is more fragile than the fish. And limit strobe use, particularly repeated flashes on a single animal.

Common seadragon populations are listed as decreasing, and the leafy faces habitat loss and low genetic diversity across a very restricted range. These are not abundant animals with room to absorb pressure.

Sources

- Australian Museum, Common Seadragon - Australian Museum, Leafy Seadragon - Fishes of Australia, Leafy Seadragon - Australian Geographic, Australia's seadragons: masters of disguise (australiangeographic.com.au) - IUCN SSC Seahorse, Pipefish and Seadragon Specialist Group: Thousands of seadragons dead in South Australia's worst recorded harmful algal bloom - InDaily: State emblem seadragon disappears from diving hotspot - Scuba Divers Federation of SA: Algal Bloom in South Australia, sdfsa.net - Scuba Divers Federation of SA: Supporting SA's Jetties (Rapid Bay exclusion zone), sdfsa.net - Marine Safety SA: Notice to Mariners No 41 of 2025 (Temporary), Old Rapid Bay Jetty prohibited area, 23 June 2025, marinesafety.sa.gov.au - Diving Adelaide: Dive the Rapid Bay Jetty - NSW Environment and Heritage: Bare Island bridge repairs - SeadragonSearch: Monitoring wild seadragon populations across Australia

Header photo: A leafy seadragon (Phycodurus eques) photographed at the Pittsburgh Zoo aquarium, by Derek Ramsey (Ram-Man), edited by IdLoveOne, CC BY-SA 2.5, via Wikimedia Commons.