Solenostomus, also known as the ghost pipefishes, false pipefishes or tubemouth fishes, is a genus of fishes in the order Syngnathiformes. Solenostomus is the only genus in the family Solenostomidae, and includes six currently recognized species. Ghost pipefishes are related to pipefishes and seahorses. They are found in tropical waters of the Indo-Pacific.

The animals, none of which are longer than 17 centimetres (6.7 in), float near motionlessly, with the mouth facing downwards, around a background that makes them nearly impossible to see. They feed on tiny crustaceans, sucked inside through their long snout. They live in open waters except during breeding, when they find a coral reef or muddy bottom, changing color and shape to minimize visibility.

In many respects, they are similar to the pipefishes, but can be distinguished by the presence of pelvic fins, a prominent, spiny, dorsal fin, and star-shaped plates on the skin. Unlike true pipefish, female ghostpipefishes use their enlarged pelvic fins to brood their eggs until they hatch.

Two fossil ghost pipefish genera, Calamostoma and Solenorhynchus, are known from the Eocene of Italy. These are placed in their own extinct subfamily, Solenorhynchinae.

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