Callionymus io is a species of dragonet endemic to the Indian Ocean waters off of Myanmar. This species grows to a length of 2.5 centimetres (0.98 in) SL.
Species taxanomy provided by GBIF Secretariat (2022). GBIF Backbone Taxonomy. Checklist dataset https://doi.org/10.15468/39omei accessed via GBIF.org on 2023-06-13; License: CC BY 4.0