Incredible video shows parasites living on deep-sea fish

Recently released images show just how some parasitic crustaceans live off their unwitting fish hosts in the deep sea.

They are part of a new paper which aims to shed light on a topic not widely researched before, partly because collecting samples often disturbs the symbiotic attachment.

So the study authors examined high-definition videos taken by remotely operated vehicles off the northeastern U.S. coast between 2013 and 2014.

As the paper states, "Only 9% of all observed fishes (25 species) were confirmed with ectoparasites."

However, as many as a third of some of the more prevalent fish species (e.g., Antimora rostrata) were observed with these attached creatures.

According to the research, the parasites included isopods and copepods which can embed their heads or legs into the fish.

And at least one was seen hosting eight leeches of its own.

Andrea M. Quattrini, one of the researchers, pointed out that parasites can be beneficial to their environment by helping to "regulate animal populations."