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

Spaghetti algae (Chaetomorpha linum)

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



Chaetomorpha linum is a delicate green seaweed. Also known as spaghetti algae, it grows as a filamentous loosely entangled mass. Usually free-floating, it may also be attached to rocks and shells. The filaments themselves are unbranched and usually between 5 and 30 cm in length. The unattached filaments are wiry, stiff and curled in appearance. It is bright light to dark green in colour.

Recorded distribution in Britain and Ireland

Found throughout the coasts of British Isles and Ireland.

Global distribution



Chaetomorpha linum is an intertidal and supralittoral species that can be found in groups of hundreds or thousands of individuals in sandy areas, on rocks or around tide pools.

Depth range


Identifying features

  • Bright green seaweed up to 30cm long.
  • Loosely entangled unattached filaments.
  • Filaments are stiff and curled.
  • Cylindrical or slightly swollen cells.
  • Cells up to 0.4 mm in diameter, 0.8 mm in length.

Additional information

Spaghetti algae, though not palatable to many herbivorous species, is popular in reef aquariums for its ability to remove nitrates, assist in buffering pH, uptake carbon dioxide producing oxygen, and assist in balancing trace elements. It also provides hiding spaces for small creatures.

Listed by

- none -

Further information sources

Search on:


  1. Burrows, E.M., 1991. Seaweeds of the British Isles. Volume 2. Chlorophyta. London: British Museum (Natural History).

  2. Dickinson, C.I., 1963. British seaweeds. London & Frome: Butler & Tanner Ltd.

  3. Hardy, F.G. & Guiry, M.D., 2003. A check-list and atlas of the seaweeds of Britain and Ireland. London: British Phycological Society

  4. 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.]

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

  6. OBIS,  2018. Global map of species distribution using gridded data. Available from: Ocean Biogeographic Information System. Accessed: 2018-08-14


This review can be cited as:

Barnes, M.K.S. 2008. Chaetomorpha linum Spaghetti algae. 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: 22/05/2008