Description: Very small, as blue-green tufts no more than 1 cm long, of branched uniseriate filaments, mucilaginous.

Habitat: Very rare. Epiphytic on algae and Zostera in the low littoral and upper sublittoral. May also occur in freshwater sites.

Distribution: Probably widely distributed around the British Isles. Recorded only from few sites in Galway Bay in Ireland. In Britain from Dorset and Northumberland. Europe: Mediterranean, Portugal, Atlantic coasts of Spain and France, Netherlands, Baltic Sea, Sweden and Norway. Atlantic coast of North America: Canada, New Hampshire, Massachusetts, Rhode Island, Connecticut and Long Island, New Jersey, Delaware, Maryland, Virginia and Florida. Further afield: Caribbean, Jamaica, West Indies, Canary Islands and California.

Distribution Map from NBN: Chroodactylon ornatum at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Chroodactylon ornatum at iNaturalist World Species Observations database.

WoRMS: Chroodactylon ornatum at World Register of Marine Species.