Australian and Japanese scientists have discovered an "alien" marine animal at the bottom of the ocean.

They have named the deep sea animal after the fictional "facehugger" xenomorph alien from the 1979 movie Alien because of it's resemblance.

The fish has been compared to the "facehugger" from Ridley Scott's 1979 science fiction film Alien. Fox

The new species of anemone has a symbiotic relationship with hermit crabs and is found at depths between of 250 and 1100 metres in waters off Japan and Australia, scientists say.

The fish has officially been named Epizoanthus xenomorphoideus.

The Queensland Museum's Dr Merrick Ekins said the fish latched onto hermit crabs.

"When this happens, Epizaoanthus produces a pseudo-shell that grows with the hermit crab, eliminating the need for the hermit crab to search for a new empty shell," Dr Ekins said.

The zoantharian species Epizoanthus xenomorphoideus, named after the fictional xenomorph alien in the famous 1979 movie Alien, latches on to a hermit crab Takeya Moritaki

This relationship may be a by-product of the great uncertainty of life deep beneath the sea.

"We think the symbiotic relationship between Epizoanthus and hermit crabs along with carcinoecium (the pseudo-shell) production may have evolved to adapt to the extreme environments of the deep sea," said researcher Hioki Kise from Japan's University of the Ryukyus.

"The deep sea harbours a very high number of species, including many not yet discovered."

The research was recently published in the journal Systematics and Biodiversity.

AAP