The oarfish (Japanese: 竜宮の使い,Ryugu-No-Tsukai) is an actual animal that is rarely sighted since it lives in the deep sea. Those fish are however also said to be mythological creatures that are either an omen for earthquakes and tragedy about to happen or the actual cause to catastrophe. In Japanese mythology they are somewhat related to sightings of mermaids. In Germany they were known as “the king of the herring” (König der Heringe) for a long time. An oarfish showing up near the surface was connected to declining numbers of fish in the area.
Sightings of oarfish may be mistaken for King-of-the-salmon sightings and the other way around.
“They taste as sweet as shrimp sashimi (…)” (Google Translate) 1)