Straightnose pipefish (Nerophis ophidion)

Classification (WoRMS)

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

Accepted name: Nerophis ophidion · Authority: (Linnaeus, 1758) · Taxonomic status: accepted · AphiaID: 127385.

Synonyms and superseded combinations recorded for this taxon: Schyphius littoralis Risso, 1827; Scyphicus teres Rathke, 1837; Scyphius littoralis Risso, 1827; Scyphius violaceus Risso, 1827; Syngnathus ophidion Linnaeus, 1758.

Source: World Register of Marine Species (WoRMS) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=127385 (CC BY 4.0). Accessed 2026-09-23.

Biology and life history (FishBase)

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

Maximum length: 29 cm · Depth range: 2–15 m · Habitat zone: demersal · Body shape: eel-like · Vulnerability index: 16.8 of 100 · Fishery importance: of no interest · Aquarium trade: never/rarely.

FishBase notes: Inhabit algal zone or eel-grass ( Zostera ) (Ref. 6733). Adults spawn in May - August . Feed on small crustaceans and fish fry (Ref. 35388). Ovoviviparous (Ref. 205). The male carries the eggs in a brood pouch which is found under the tail (Ref. 205). Consistent paternity is ensured despite brooding of embryos on the outside the male's body. Events of cuckoldry by sneaker males is ruled out through genetic paternity analyses based on molecular markers (Ref. 81011). Each male carries eggs from a single female but females may deposit eggs on several brooding pouches (Ref. 81011).

Source: FishBase species summary (SpecCode 1331) — https://www.fishbase.se/summary/Nerophis-ophidion.html (CC BY-NC 3.0 — non-commercial use only). Accessed 2026-09-23.

Distribution and occurrence records (GBIF)

3,386 georeferenced occurrence records for Nerophis ophidion are published through GBIF from 29 countries or marine areas. The map above plots 159 distinct locations from a sample of 3,000 records, omitting 83 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: Finland (838); Sweden (831); Poland (474); France (468); Norway (370).

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

Source: GBIF Occurrence Search (taxonKey 2333329) — https://www.gbif.org/occurrence/search?taxon_key=2333329&has_coordinate=true (records CC0 / CC BY); WoRMS distribution records (MarineRegions) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=127385 (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 Nerophis ophidion (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 198764) — https://www.iucnredlist.org/species/198764/0; GBIF IUCN Red List category endpoint (taxonKey 2333329) — https://api.gbif.org/v1/species/2333329/iucnRedListCategory. Accessed 2026-09-23.

Description and natural history (Wikipedia)

The straightnose pipefish initially gives the impression of being a worm. The head is tiny and resembles that of a seahorse, to which this fish is closely related. The body is round in cross-section and the fins are tiny. The only fish with which it might be confused is the broadnosed pipefish (Syngnathus typhle) but that is more robust and has a hexagonal cross-section. The general colour of the straightnose pipefish is green with a yellowish belly. The female has pale blue markings on the head and body and both sexes become more colourful at breeding time when the male's snout turns yellow. The average size is about 15 to 20 cm with a maximum of 30 cm.

This fish is found in the North-eastern Atlantic along the coasts of Europe, its range extending from southern Norway to Morocco. It is also present in the Baltic, the Mediterranean, and the Black Sea. It inhabits sandy bottoms and is part of the fouling community, at depths from 2 to 15 m.

The straightnose pipefish lives among eelgrass and seaweed with its tail wrapped around the vegetation and its head elevated. Here it is well-camouflaged, and feeds on zooplankton and copepods by sucking them in.

This species of pipefish is used as a model to study mate choice and sex role-reversal. Like other species of pipefish and the closely related seahorses, the straighnose pipefish exhibits male parental care, meaning that female reproductive success is limited by her ability to court and mate with a suitable male. In the straighnosed pipefish, female-female competition and mate choice by males has resulted in female-specific coloration, female ornamental skin folds, and more active courtship in females.

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