It forms mat-like colonies on rocks, or sometimes on the mollusc shells occupied by hermit crabs.

[3] That placement remained unchallenged for over a century until phylogenetic studies began to be carried on the Hydractiniidae, which revealed that Hydractinia required splitting.

[2] This hydroid is native to the northeastern Pacific Ocean, its range extending from Vancouver Island to Monterey Bay, California.

[2] Species of hydroid are sometimes found growing on the mollusc shells occupied by hermit crabs.

In one such case, a colony of Schuchertinia milleri was found on the shell occupied by the whiteknee hermit crab Pagurus dalli (which is more usually overgrown by a species of sponge).