A small southern seahorse with a short snout and a shaggy mane of skin filaments, usually in pairs on brown algae.
Between about 10 and 15 cm depending on the source, and most sources are nearer 10. The snout is very short. The crown on the head is tall and clearly raised and is topped with fleshy filaments, which is where the alternative name knobby seahorse comes from, and there are more fleshy tendrils on the head and body. The colour runs from drab grey to bright yellowish-orange, with black spots and white eye-like marks, and the dorsal fin carries two dark bands running along it.
Young big-bellied seahorses are the confusion, and the tall filament-tipped crown with a short snout separates this one. A Western Australian animal of similar appearance may or may not be the same species; that is unresolved.
It lives in shallow seagrass and large seaweed in bays, estuaries and sheltered coastal reef between the surface and about 15 m, and unusually for a seahorse it gathers in groups of both sexes in weed patches. Males carry fifty to a hundred eggs for about twenty-five days in summer.
It is a southern Australian fish — Victoria, Tasmania and South Australia — and not a Great Barrier Reef species. It is on Appendix II of CITES.
Ratings are per location: 1 means found on most dives that look for it, 5 means a handful of records. Where enough dives have been logged the figure is calculated from them; otherwise it is an editorial estimate, and says so. We publish habitat and destination, not the dive site.