Ostorhinchus cyanosoma is a Cardinalfish from the Indo-West Pacific. It grows to a size of 8cm in length although the average length is 6cm. It lives in clear water areas of lagoons, and shallow reefs. It inhabits waters from 1 to 50m and makes its home under ledges, in holes and aggregations, and in between the spines of sea urchins. Although it can go down to 50m it usually stays at around 1 to 15m. The fish is colored with a blueish tinge with six orange-yellow stripes. Ostorhinchus cyanosoma is harmless to humans.