A sea fir (Aglaophenia kirchenpaueri)

Distribution data supplied by the Ocean Biodiversity Information System (OBIS). To interrogate UK data visit the NBN Atlas.Map Help



A large, colonial hydroid that grows up to 20 cm high, with broad unbranched stems. The side branches are long and straight in alternating series on opposite sides giving a feather-like colony. The colour of living specimens is brown with a green tinge due to zooxanthellae. The feeding polyps are borne in a single series along the side branches, each surrounded by three defensive polyps. The hydrothecae, a supporting, nonliving, protein-chitinous envelope surrounding the stalk, is slightly broader than long and the rim has nine projecting teeth. The corbula or basket is up to 3 mm long, at the base of the branch, close to the main stem with up to ten per stem. Some of the ribs forming the basket are unfused leaving open gaps.

Recorded distribution in Britain and Ireland

Found around the south-west coasts of England, Wales and Ireland.

Global distribution



Found on hard substrata, the seaweed Cystoseira spp. and coralline algae on the lower shore and shallow sublittoral.

Depth range


Identifying features

  • Broad, un-branched, pinnate stems, in groups along a basal stolon.
  • Hydrothecae slightly broader than long, the rim with nine projecting teeth.
  • Very short nematotheca in front of each hydrothecae, and one on each side at the top.
  • Each hydrotheca has a prominent internal septum.
  • Corbula up to 3 mm long, at base of branch, close to main stem.
  • Up to 10 per stem; some of the ribs forming the basket are not fused, leaving open gaps.

Additional information

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Listed by

- none -


  1. Hayward, P., Nelson-Smith, T. & Shields, C. 1996. Collins pocket guide. Sea shore of Britain and northern Europe. London: HarperCollins.

  2. Howson, C.M. & Picton, B.E., 1997. The species directory of the marine fauna and flora of the British Isles and surrounding seas. Belfast: Ulster Museum. [Ulster Museum publication, no. 276.]

  3. Moore, J., 2002. An atlas of marine Biodiversity Action Plan species and habitats and Species of Conservation Concern in Wales, 2nd edn. Report to the Countryside Council for Wales, CCW Contract Science Report no. 509.

  4. Picton, B.E. & Costello, M.J., 1998. BioMar biotope viewer: a guide to marine habitats, fauna and flora of Britain and Ireland. [CD-ROM] Environmental Sciences Unit, Trinity College, Dublin.

  5. Svoboda, A. & Cornelius, P. F. S., 1991. The European and Mediterranean species of Aglaophenia (Cnidaria: Hydrozoa). Zoologische Verhandelingen, 274, 72 pp.


  1. NBN (National Biodiversity Network) Atlas. Available from: https://www.nbnatlas.org.

  2. OBIS (Ocean Biodiversity Information System),  2024. Global map of species distribution using gridded data. Available from: Ocean Biogeographic Information System. www.iobis.org. Accessed: 2024-07-21


This review can be cited as:

Wilson, E. 2008. Aglaophenia kirchenpaueri A sea fir. In Tyler-Walters H. and Hiscock K. Marine Life Information Network: Biology and Sensitivity Key Information Reviews, [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 21-07-2024]. Available from: https://marlin.ac.uk/species/detail/1262

Last Updated: 16/06/2008