[2] This is the largest sea anemone in the northeastern Atlantic; the smooth column can be 30 cm (12 in) in height with a pedal disc wider than this.

It occurs at depths down to about 100 m (330 ft), on rocks, in caves, on pebbles, on molluscs such as mussels, on wharves and jetties, on floating objects, nets and ropes.

[3] Metridium dianthus is a suspension feeder, spreading its plume of tentacles and catching small organisms as they float past.

These include the eggs and larvae of molluscs, polychaetes, ascidians, amphipods, copepods, barnacles, shrimps and other crustaceans, as well as foraminifera and diatoms.

Batches of eggs are emitted by the female at intervals of two to ten days, not through the siphonoglyphs, as might be expected, but through slits in the body wall known as cinclides.