Callionymus filamentosus, the Blotchfin dragonet, is a species of dragonet native to the Indian Ocean and the western Pacific Ocean. It also now occurs in the Mediterranean Sea having invaded as a Lessepsian migrant through the Suez Canal. This species occurs at depths of from 16 to 350 metres (52 to 1,148 ft). This species grows to a length of 20 centimetres (7.9 in) TL.