Streaming Axe Marlin

A fish with unique morphology and Fontaine's cousin to the butterfly fish. This fish has a broad skeleton and a unique curved body. Legend has it that the first fishermen to catch this fish had their rods tilted at the end of the tail fin and found that the two, when combined, resemble a polearm, hence giving rise to the name "Axe Marlin." This name has made much more of an impression than its scientific name, the "Anchor Hook Butterfly," and it is thus colloquially used amongst most people.
It is said that these sea-blue Axe Marlins were a special type that migrated from Sumeru to Fontaine. Compared to their more mild-tempered cousins in Sumeru, Streaming Axe Marlins are tougher and can survive in far more inhospitable environments. They are also known to travel extremely long distances, comparable even to those covered by some merchant vessels. As a result, some sailors see them as an emblem of courage and patience.