Rosenblattia robusta is a species of deepwater cardinalfish, the only member of the genus Rosenblattia, found circumglobally in southern temperate waters. Its length is between 1.97 and 4.72 in (5 and 12 cm).
Rosenblattia robusta is deep bodied with a humped back above the pectoral fin area, and a single keel on each side of the caudal peduncle.
Adults are a uniform golden brown with a black lining to the mouth and gill cavity. Juvenile fish are a pale gold with a white caudal peduncle separated by a black band that continues forward along the dorsal and anal fin bases.
This species is a plankton feeder with curved conical teeth that lives in midwater on the boundary between the mesopelagic and bathypelagic zones.
Illustration by Dr Tony Ayling