By Amy Morton
Geographic Range
Solenostomus paradoxus can be found in the tropical and subtropical waters of the Indo-Pacific region. It has been observed in and around the Red Sea, the Maldives, Indonesia, southern Japan, the Marshall Islands, New Guinea, off the east coast of Africa and also off the east coast of Australia (Orr and Fritzsche, 1993).
Biogeographic Regions:
indian ocean (native 
); pacific ocean (native ).
Habitat
Solenostomus paradoxus is found in shallow tropical waters, mainly near coral reefs, rocky dropoffs or seaweed beds. S. Paradoxus is usually observed in 3-25 meters of water (
http://www.austmus.gov.au/fishes/fishfacts/fish/sparadox.htm; http://www.britannica.com/bcom/eb/article/0/0,5716,61650+1+60134,00.html).
Physical Description
Solenostomus paradoxus possesses the elongate snout and laterally compressed body that are typical of all syngnathoid fishes. More specific to the solenostomids is a dermal skeleton composed of stellate plates, a head region that represents over one third of the total body length and the presence of pelvic fins, two separate dorsal fins, an anal fin and a large ventral fin. Solenostomus paradoxus is further distinguished by the presence of abdominal spinules, additional plates at the dorsal- and anal-fin bases and the presence of nasal lamellae filling the nasal cavity of males. There is no body color representative of S. paradoxus. Typical color patterns include dark red with yellow and orange splotches and yellow with lighter spots.
The Harlequin Ghost Pipefish is sexually dimorphic. Female S. paradoxus average 130 mm; males on average are 37% smaller. The main difference between males and females is the presence of a ventral brood pouch in females. This difference is most noticeable in the margins of the pelvic fins which are apposed in females and free in males (Wetzel and Wourms, 1995; Orr and Fritzsche, 1993; http://www.austmus.gov.au/fishes/fishfacts/fish/sparadox.htm).
Some key physical features:
bilateral symmetry .
Reproduction
Solenostomus paradoxus is an external skin-brooding species. Embryos are enclosed in an envelope and attached to special epidermal cells called cotylephores. In S. paradoxus, these cells occur only on the inside surface of the pelvic fins of females (the brooders in this species.) The pelvic fins of females are expanded and connect to the body and to each other in order to form a brood pouch. Females carry eggs in this pouch during the incubation period. This method allows the female to move her young to a site that is favorable for survival and also decreases the risk of predation during the developmental stage. Clutch size in S. paradoxus is variable. It has been estimated that a normal brood size may be as high as 350 (Wetzel et al., 1997; Wetzel and Wourms, 1995; Orr and Fritzsche, 1993).
Behavior
The species is normally solitary. It has, however, been observed in pairs or small groups. Solenostomus paradoxus is a weak swimmer, propelling itself by rapidly fanning its fins. While this technique allows for very precise control of body position, the range of individuals in this species is limited. Unfortunately, very little is known regarding the behavior of this organism (http://www.britannica.com/bcom/eb/article/0/0,5716,61650+1+60134,00.html; Paxton and Eschmeyer, 1998).
Key behaviors:
natatorial ; motile .
Food Habits
Solenostomus paradoxus is an ambush predator that feeds by sucking small aquatic organisms rapidly into the mouth (http://www.britannica.com/bcom/eb/article/0/0,5716,61650+1+60134,00.html).
Economic Importance for Humans: Negative
This organism does not appear to adversely affect humans.
Economic Importance for Humans: Positive
Underwater photographers and scuba divers are highly attracted to the unique appearance of Solenostomus paradoxus (http://www.coralrealm.com/fish/ghostpipe.ihtml).
Conservation Status
IUCN Red List: [link]:
Not Evaluated.
US Federal List: [link]:
No special status.
CITES: [link]:
No special status.
No specific conservation measures are currently in effect.
Other Comments
Paradoxus is derived from the Greek, meaning contrary to expectation (Wetzel and Wourms, 1993).
Contributors
Amy Morton (author), University of Michigan.
William Fink (editor), University of Michigan.
