Flame shell beds

The flame shell or file shell is a bivalve mollusc that forms dense beds, which may support hundreds of species.

Flame shells (Limaria hians) live hidden on the seabed in nests, which they build from shells, stones and other materials. Hundreds of nests can combine to form a dense bed, which raises and stabilises the seabed and makes it more attractive to many other creatures.

A Loch Fyne study found that six nest complexes supported:

  • 19 algae species
  • 265 invertebrate species

Flame shell beds offer good attachment for scallop spat, which fall from plankton and young fish are often associated with the beds. Individual flame shells, which grow up to 4cm in length, may also live under stones or in kelp holdfasts.

In British waters, this species lives mainly on western coasts, with the largest known flame shell bed in Loch Alsh. Individuals have been found at depths of 100m, while flame shell beds usually occur at depths of between 5m and 30m, though they can be found from the low-tide mark. Flame shell beds develop mostly on seabeds of coarse sand, gravel and shells, often in areas with moderate or strong water currents.

Some of our best examples are in sea lochs:

  • Loch Fyne
  • Loch Sunart
  • Loch Carron
  • Loch Creran
  • Loch Alsh
  • Loch Broom
Map of flame shell beds in the UK

Threats to flame shell beds

Flame shell beds are vulnerable to mechanical disturbance, particularly from bottom trawls and dredges. Extensive flame shell beds are rare.

Protection of flame shell beds

Flame shell beds are a priority marine feature in Scotland’s seas and a protected feature of Nature Conservation Marine Protected Areas.

This habitat is also a UK Biodiversity Action Plan priority habitat.

Find out more

Learn more about the flame shell on the NBN Atlas Scotland website.

Read about our protected species of invertebrate.

Watch the video, A flame shell on the move, on our YouTube channel:


Flame shells (Limaria hians) are beautiful bivalve molluscs with a spectacular fringe of orange tentacles - also known as file shells. Flame shells live on the seabed inside nests, which they build from shells, stones and other materials around them. Although rarely seen by divers, in this rare clip, a flame shell seeks shelter after nest disturbance.