Greater pipefish (Syngnathus acus)

Classification (WoRMS)

Full classification as recorded by WoRMS: Kingdom: Animalia · Phylum: Chordata · Class: Teleostei · Order: Syngnathiformes · Family: Syngnathidae · Genus: Syngnathus.

Accepted name: Syngnathus acus · Authority: Linnaeus, 1758 · Taxonomic status: accepted · AphiaID: 127387.

Synonyms and superseded combinations recorded for this taxon: Dermatostethus punctipinnis Gill, 1862; Sygnathus acus (Linnaeus, 1758); Syngnathus alternans Günther, 1870; Syngnathus brachyrhynchus Kaup, 1856; Syngnathus delalandi Kaup, 1856; Syngnathus rubescens Risso, 1810; Typhle heptagonus Rafinesque, 1810.

Source: World Register of Marine Species (WoRMS) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=127387 (CC BY 4.0). Accessed 2026-09-23.

Biology and life history (FishBase)

Measured values published by FishBase for Syngnathus acus. Only fields the database actually holds for this species are shown; these are database values, not aquarium guidance.

Maximum length: 50 cm · Depth range: 0–110 m · Habitat zone: demersal · Body shape: eel-like · Vulnerability index: 40 of 100 · Fishery importance: of no interest · Aquarium trade: commercial.

FishBase notes: Found in coastal and estuarine waters to depths of at least 110 m (Ref. 4281); on sand, mud and rough bottoms. Common amongst algae and eel-grass ( Zostera ) (Refs. 4146, 6733, 88187). Feeds mainly on small crustaceans (Ref. 85544). It is parasitised by the monogenean Gyrodactylus eyipayipi on the body surface, inside the flute and male brood pouch (Ref. 124059).

Source: FishBase species summary (SpecCode 1770) — https://www.fishbase.se/summary/Syngnathus-acus.html (CC BY-NC 3.0 — non-commercial use only). Accessed 2026-09-23.

Distribution and occurrence records (GBIF)

14,915 georeferenced occurrence records for Syngnathus acus are published through GBIF from 42 countries or marine areas. The map above plots 175 distinct locations from a sample of 3,000 records, omitting 133 inland records that carry an institution's coordinates rather than a collection site; it shows where the species has been observed and reported, not a modelled range.

Most records by country or area: Netherlands (4,462); United Kingdom of Great Britain and Northern Ireland (3,404); France (1,086); Belgium (981); Ireland (964).

The full country table, WoRMS marine regions and the sampling notes are on this species' Distribution page.

Source: GBIF Occurrence Search (taxonKey 2332927) — https://www.gbif.org/occurrence/search?taxon_key=2332927&has_coordinate=true (records CC0 / CC BY); WoRMS distribution records (MarineRegions) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=127387 (CC BY 4.0); Natural Earth 110m basemap — https://www.naturalearthdata.com/ (public domain). Accessed 2026-09-23.

Conservation status (IUCN Red List)

The IUCN Red List assesses Syngnathus acus Linnaeus, 1758 as Least Concern (code LC). No trend, population estimate or threat analysis is given here, because none is available from this source without the Red List API; follow the source link for the full assessment, including its date.

Source: IUCN Red List of Threatened Species (taxon 250588960) — https://www.iucnredlist.org/species/250588960/0; GBIF IUCN Red List category endpoint (taxonKey 2332927) — https://api.gbif.org/v1/species/2332927/iucnRedListCategory. Accessed 2026-09-23.

Description and natural history (Wikipedia)

The genus name Syngnathus derives from the Greek, syn, symphysis meaning grown together and gnathos meaning jaw. The Latin species' name acus means needle.

The greater pipefish has a long segmented armoured body, angular in cross section and stretching up 45 cm long with its stiff appearance. It ranges a color brown to green in with broad alternating light and dark hue along it. Its customized by a long snout with mouth on end and a slight hump on the top of the body just behind the eyes.

The fish is generally 33 cm to 35 cm in length with a reported maximum length of 47 cm. They are almost square in each segment of the body, and known to feel rigid when handled. The greater pipefish has distinctive body rings which are a sandy brown with darker bars covering its body in between.

The anatomy of fish vary through the sex. The top third of the females belly is deep (when egg bound), twice the breadth of the lower two thirds below the vent. The male is the "tailing" with the twin folds below the vent. The folds of the skin make the middle third and during the "brooding" of the young they swell in size until the young are released from the pouch (at a size of 22 mm to 35 mm).

These fishes feed on live mysids and small prawns. They are ovoviviparous and reproduce usually three times each year. A few females deposit partial clutches under the tail into the male's brood pouch, that may contain up to 400 eggs.

The greater pipefish is found all around the British Isles and is regularly found in the Mediterranean Sea.

These fishes are common on southerly and westerly coasts in a variety of habitats, often amongst seaweeds and seagrass.

The southern African species Syngnathus temminckii (Kaup, 1856) was until recently synonymised with S. acus. However, morphological data clearly show that it is distinct, and genetic data indicate that it is not even the sister taxon of S. acus, but of another southern African species, the river pipefish S. watermeyeri.

Source: Wikipedia: Greater pipefish — https://en.wikipedia.org/wiki/Greater_pipefish (CC BY-SA 4.0). Accessed 2026-09-23.