information on the biology of species and the ecology of habitats found around the coasts and seas of the British Isles

Trumpet anemone (Aiptasia mutabilis)

Distribution data supplied by the Ocean Biogeographic Information System (OBIS). To interrogate UK data visit the NBN Atlas.
Only coastal and marine records shown



A tall anemone, up to 12 cm high, the slender column flaring outwards to the broad oral disc. The tentacles, up to about 100, are steeply graduated in size, the inner ones being very long in extension, stout at the base and tapering to fine points. They are perfectly retractile but rarely retracted. The column is brown often with irregular streaks of opaque white and the tentacles are brown becoming paler and whitish toward their tips. The overall brownish colouration may have a blue tint.

Recorded distribution in Britain and Ireland

Found North Wales and Pembrokeshire and round the coast of south and west England, including the Scilly Isles. Its occurrence is very localized.

Global distribution



Found on the lower shore in pools, under stones or beneath overhangs, often amongst algal holdfasts, particularly Laminaria and Saccorhiza. Sometimes abundant on infralittoral rock at wave sheltered locations.

Depth range


Identifying features

  • Lightly adherent base, usually small and rarely much wider than column.
  • The junction between basal disc and column (the limbus) is not sharply defined.
  • Numerous minute, adhesive spots (or rugae) present on lower half of column by which anemone may attach in preference to base.
  • Tiny perforations (cinclides) fairly prominent when column well extended.
  • Thread-like acontia emitted reluctantly but often visible through translucent column wall.

Additional information

Possibly conspecific with Aiptasia couchii (Cocks, 1850) although this may be a distinct species (R B Williams).

Listed by

- none -

Further information sources

Search on:


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

  2. Hayward, P.J. & Ryland, J.S. (ed.) 1995b. Handbook of the marine fauna of North-West Europe. Oxford: Oxford University Press.

  3. 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.]

  4. Manuel, R.L., 1988. British Anthozoa. London: Academic Press.[Synopses of the British Fauna, no. 18.]

  5. 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.

  6. National Biodiversity Network (NBN) Atlas website. Available from:  Accessed 01 April 2017


This review can be cited as:

Wilson, E. 2008. Aiptasia mutabilis Trumpet anemone. In Tyler-Walters H. and Hiscock K. (eds) Marine Life Information Network: Biology and Sensitivity Key Information Reviews, [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 14-08-2018]. Available from:

Last Updated: 02/09/2008