- Kingdom: Animalia
- Phylum: Chordata
- Subphylum: Vertebrata
- Superclass: Gnathostomata
- Class: Actinopterygii
- Order: Syngnathiformes
- Family: Syngnathidae
- Scientific name: Syngnathus acus
- Norwegian: stor havnål
The slender body can reach a length of 50 cm and this makes it the largest of our pipefishes. The color varies from light green to dark brown. The long cylindrical snout constitutes more than half of the head's length. A cross section of the body is shaped like a hexagon, rather than an oval. The tiny tail and ventral fins contribute to its poor swimming capabilities.
It is usually found between seaweed from the intertidal zone and down to 20 meters, but has been reported as deep as 90 meters. It is also common on sandy or muddy substrate in the mouths of estuaries.
The great pipefish can be found on the Faroes, the British Isles and along the Atlantic coasts, from Norway to Morocco. It is also registered at the Azores, in the Mediterranean and the Black Sea.