Sio is a monotypic genus of fish in the family Melamphaidae, the ridgeheads. The only species is Sio nordenskjoldii, or Nordenskjold's bigscale. It has a circumglobal distribution on the southern hemisphere at depths from .
Etymology The genus names refers to the Scripps Institute of Oceanography, abbreviated as SIO.
Description This species grows to a length of SL.
Conservation There are no known threats to this species. It is not caught by commercial fisheries.
References