Janss’ pipefish uses rapid waving of its dorsal and pectoral fins to swim (6), and is often seen swimming upside down (3). This species typically occurs in pairs, and each pair actively maintains a ‘cleaning station’ at the entrance to a cave or crevice, where the male and female work together to pick parasites off visiting fish (1) (2) (3). Like other members of the Syngnathidae family, Janss’ pipefish has no teeth (5) (6), instead sucking prey into its tubular snout using a pipette-like action (2) (3) (6).
Syngnathid species have an unusual breeding strategy in which the male rather than the female becomes pregnant. The female Janss’ pipefish lays its eggs onto a specialised, partly exposed ‘brood pouch’ on the underside of the male’s body, where the eggs are fertilised and are incubated by the male until they hatch (1) (2) (3) (4) (5) (6). The male Janss’ pipefish is able to start brooding eggs once it reaches a total length of about 8 centimetres (3), and like other Doryrhamphus species it is likely to carry about 80 to 150 eggs at a time (1).
The eggs of Janss’ pipefish have not yet been described, but as in most other syngnathids they are likely to be spherical. The larvae of this species resemble miniature versions of the adults. Little other information is available on the breeding behaviour of Janss’ pipefish, but many other syngnathid species are known to form monogamous pair bonds, and some pairs even perform daily greeting rituals during the breeding season (3).
Janss’ pipefish is likely to be vulnerable to a range of predators, such as sharks, rays, other fish, sea birds, turtles and marine mammals (3).