Della famiglia dell'ippocampo, è un suo cugino orizzontale; indicatore della purezza delle acque.

Tassonomia:

Domain: Eukaryota - Whittaker & Margulis,1978
Kingdom: Animalia - Linnaeus, 1758 - animals
Subkingdom: Bilateria - (Hatschek, 1888) Cavalier-Smith, 1983
Branch: Deuterostomia - Grobben, 1908
Infrakingdom: Chordonia - (Haeckel, 1874) Cavalier-Smith, 1998
Phylum: Chordata - Bateson, 1885 - Chordates
Subphylum: Vertebrata - Cuvier, 1812 - Vertebrates
Infraphylum: Gnathostomata - Auct. - Jawed Vertebrates
Superclass: Osteichthyes - Huxley, 1880 - Bony Fishes
Class: Actinopterygii - Huxley, 1880 - Ray-Finned Fishes
Subclass: Actinopterygii - Ray-Finned Fishes
Infraclass: Actinopteri
Cohort: Clupeocephala
Superorder: Acanthopterygii
Order: Syngnathiformes - Pipefishes And Seahorses
Family: Syngnathidae - Pipefishes and Seahorses
Subfamily: Syngnathinae
Genus: Syngnathus - Linnaeus, 1758
Specific name: acus - Linnaeus, 1758
Scientific name: - Syngnathus acus Linnaeus, 1758