Flattened side to side and usually dark, hanging head-down in seagrass where it reads as a blade rather than a fish.
To about 16 cm. Very slender, with a broad flattened leaf-like trunk in females. The colour varies with the habitat — greenish, brownish or bright red. Females have dark bands across the underside of the widened trunk, often with an orange line along the side, and the trunk swells in the breeding season. There is no tail fin.
The spotted pipefish is the confusion and the check is where the dorsal fin starts: over the fifth to ninth body ring on this species, over the eleventh to thirteenth on the spotted pipefish. A third species, red and living deeper on sponge and red algae, was described from New South Wales in 2020.
It lives in sheltered seagrass and weed beds in bays and estuaries, from the intertidal to about 35 m, clinging to fronds with a nearly prehensile tail and sucking in planktonic copepods through its long snout. Males brood up to forty-one eggs and the fish matures at around 7 cm.
It runs from southern Queensland round to Shark Bay in Western Australia, including Tasmania, and also occurs in New Zealand. It is a temperate fish. It is also called the black pipefish.
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.