''Hydractinia'' is a genus of commensal

athecate hydroids Anthoathecata, or the athecate hydroids, are an order of hydrozoans belonging to the phylum Cnidaria. A profusion of alternate scientific names exists for this long-known, heavily discussed, and spectacular group. It has also been called Gymno ...

which belong to the family Hydractiniidae. ''Hydractinia'' species mostly live on hermit-crabbed marine gastropod shells. One species, ''

Hydractinia echinata ''Hydractinia echinata'' is a colonial marine hydroid which is often found growing on dead, hermit-crabbed shells of marine gastropod The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates w ...

'', is commonly known as

snail fur ''Hydractinia echinata'' is a colonial marine hydroid which is often found growing on dead, hermit-crabbed shells of marine gastropod The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates w ...

. Another species, ''H. minoi'', is known to be commensal with stingfishes of the genus ''

Minous ''Minous'', is a genus of marine ray-finned fishes, it is the only genus in the tribe Minoini, one of the three tribes which are classified within the subfamily Synanceiinae within the family Scorpaenidae, the scorpionfishes and their relatives. ...

''.

Species

References

''Hydractinia''
at World Register of Marine Species Hydractiniidae Hydrozoan genera {{anthoathecata-stub