Synagrops japonicus is a species of ray-finned fish within the family of Synagropidae.[1] It was described by Döderlein in 1883.
It can be found from Eastern Africa up to the islands of Hawaii. Most of them live at a depth of 100-800 m (330-2600 ft).
They have 10 dorsal spines, 9 dorsal soft rays, 2 anal spines, 7 anal soft rays, and 25 vertebrae. The body is elongated and compressed with large cycloid scales. The body is blackish-brown when young, though after maturing into adults, it becomes paler.