Butterfly kingfish

The butterfly kingfish (Gasterochisma melampus) is an ocean-dwelling ray-finned bony fish in the mackerel family, Scombridae – a family which it shares with the tunas, mackerels, Spanish mackerels, and bonitos. Unlike the 50 species from those four tribes, however, this species is unique in that it is the only scombrid to be classified apart from the rest, into the subfamily Gasterochismatinae and genus Gasterochisma.

Although taxonomists and the Food and Agriculture Organization of the United Nations have accepted the name "butterfly kingfish", this fish has had many common names, including big-scaled mackerel, bigscale mackerel, butterfly mackerel, butterfly tuna, scaled tunny, scaly tuna, and others. In 1993, the U.S. Food and Drug Administration gave approval for this fish to be marketed simply as "mackerel".