Fish
Leafy seadragon
Phycodurus eques
A fish that looks exactly like a drifting piece of seaweed — the most spectacular camouflage in temperate marine wildlife.
🗺️ Geographic range
Endemic to southern and western Australia, from the coasts of South Australia to southwestern Western Australia.
📊 Population
No precise global population figure; considered to be declining locally due to coastal pollution and collection for the aquarium trade (IUCN, near threatened).
⚠️ Threats
Coastal pollution
Declining coastal water quality locally affects the seaweed meadows it entirely depends on for camouflage and food.
Source: Australian Museum
Collection for the aquarium trade
Its popularity among aquarium keepers leads to targeted collection in certain Australian coastal areas.
Source: Australian Museum
Habitat
- Indian Ocean · Kelp forest / seaweed meadow · Epipelagic zone · Permanent
Behaviour
- Diet
- Feeds on mysid shrimp and small crustaceans, sucked up through a toothless tubular snout.
- Hunting
- An ambush hunter: it drifts motionless until prey passes within reach.
- Reproduction
- The male carries around 250 eggs under his tail for nearly 9 weeks, until they hatch.
Physiology
- Anatomy
- The body is covered in leaf-shaped appendages that mimic drifting seaweed fronds.
- Adaptations
- Swims very slowly by rippling nearly transparent fins, so as never to give away its silhouette.
⚡ Its extraordinary abilities
- Near-perfect camouflage mimicking the surrounding seaweed
- The male carries and protects the eggs until they hatch
🏆 Records
The most accomplished camouflage in a temperate fish
Its appendages mimic seaweed fronds to the point of making it nearly undetectable.
If you cross paths with this animal…
Risk: No danger to humans.
Behaviour: Stays still or drifts slowly; rarely flees actively.
Advice: A protected species in Australia: never touch or collect one.
💡 Did you know?
- The official marine emblem of the state of South Australia.
- Its leaf-shaped appendages serve camouflage only — it cannot use them to swim.