This impressive movie was taken at a depth of 2400 m. The fish is a Threadfin Seasnail, Rhodichthys regina (family Liparidae). Thank you to Dr David Stein for identifying the fish.
The movie is over 4 minutes long. It is worth persevering because the ROV moves in very close to the fish in the second half of the clip. The fish does not reappear after it swims away towards the end of the footage.
Snailfishes occur mostly in cool to cold waters of the northern hemisphere and Antarctica. The Threadfin Seasnail is found from the Arctic to Northeast Atlantic.
At least 30 species in three genera occur in Australian waters often in deep water. Who knows how many we are yet to discover.
View footage of a 'floating' snailfish on the Northwest Shelf, Western Australia.