Andaman Sea to Bali. Abundant on Java´s north coast, but uncommon in Bali where it has to compete with congeners. Its sibling Cirrhilabrus lyukyuensis ranges intermittently to Bali. C. cyanopleura occurs on coastal and inner reefs, sometimes forms lage schools when feeding on zooplankton, Males are identified by the patch of scales with purple to blue margins in the centre of the body and none below the level of the pectoral fin base. Length to 11cm.