Sundadanio atomus

{{Short description|Species of fish}}

{{speciesbox

| image =

| status = LC | status_system = IUCN3.1

| status_ref = {{cite iucn |author=Lumbantobing, D. |year=2019 |title=Sundadanio atomus |volume=2019 |page=e.T91075292A91075296 |doi=10.2305/IUCN.UK.2019-2.RLTS.T91075292A91075296.en |access-date=17 November 2022}}

| taxon = Sundadanio atomus

| display_parents = 3

| authority = Conway, Kottelat & H. H. Tan, 2011

}}

Sundadanio atomus is a species of freshwater ray-finned fish belonging to the family Sundadanionidae, the tiny danios.{{Cof genus|genus=Sundadanio|access-date=27 January 2025}} It is endemic to Singkep, off Sumatra (Indonesia). It lives in peat swamp forests.

Sundadanio atomus reaches a maximum size of {{convert|1.6|cm|abbr=on}} standard length.