Pachycerianthus fimbriatus is a cerianthid anemone that burrows in substrate and lives in a semi-rigid tube made of felted nematocysts.

Like most anemones, the tube-dwelling anemone contains stinging cells or nematocytes along its tentacles, however, the cells are not toxic to humans.

It is considered to be synonymous with Pachycerianthus plicatus which was described from the Pacific Ocean coast of North America.

[2] Pachycerianthus fimbriatus feeds on small crustaceans.

The giant nudibranch Dendronotus iris has been documented to prey upon P. fimbriatus.