Ghost pipefishes, also known as false pipefishes, are a small family of 5 members of the order Syngnathiformes. They have an incredible ability to mimic their environment which, combined with their small size, means that they often go unnoticed by divers, hence their common name "ghost".
They are usually found floating next to their hosts, corals, gorgonians or similar algae. They are small fish, not exceeding 16 centimeters in length, with large fins that are often ornamental so as not to be noticed, and come in a variety of colors, including red, white, yellow, yellow, black, or green, depending on the environment. Ghost pipefish have hard plates on their bodies for defense, and their tubular snouts are similar to those of seahorses, to which they are closely related.
There are five known species of ghost pipefish: Decorated ghost pipefish (Solenostomus armatus), Robust ghost pipefish (Solenostomus cyanopterus), Halimeda ghost pipefish (Solenostomus halimeda), Delicate ghost pipefish (Solenostomus leptosoma), and Harlequin ghost pipefish (Solenostomus paradoxus).
All members of this family have a similar morphology, but vary considerably in camouflage, coloration, and size, ranging from 5 centimeters for the Halimeda Ghost Pipefish to 16 centimeters for the Robust Ghost Pipefish.
Robust ghost pipefish (Solenostomus cyanopterus). Pic by PacificKlaus
Delicate ghost pipefish (Solenostomus leptosoma). Source
These fish are head down when feeding, which is most of the day, absorbing tiny crustaceans and plankton through their snout. This position also helps them mimic their environment: crinoids, soft corals, sea grass, algae and hydroids.
It is the female ghost fish that incubates the fertilized eggs. After incubation, the eggs are released and travel with the currents until they find a suitable place to live.
The ghost pipefish's main threat is from humans, as they are commercialized as aquarium ornaments.