:Sundadanio

{{Short description|Genus of fishes}}

{{automatic taxobox

| image = Sundadanio cf. axelrodi.jpg

| image_caption = Sundadanio axelrodi

| taxon = Sundadanio

| display_parents = 3

| parent_authority = Mayden & W. J. Chen, 2010

| authority = Kottelat & K. E. Witte, 1999{{Cof family|family=Sundadanionidae|access-date=27 January 2025}}

| type_species = Rasbora axelrodi

| type_species_authority = Brittan, 1976

}}

Sundadanio is a genus of freshwater ray-finned fishes and it is one of two genera in the family Sundadanionidae, known as the tiny danios. These fishes are typically found in peat swamps and blackwater streams, in Borneo and Sumatra (as well as nearby smaller islands) in southeast Asia.{{cite journal |last1=Conway |first1=K.W. |last2=Kottelat |first2=M. |last3=Tan |first3=H.H. |year=2011 |title=Review of the Southeast Asian miniature cyprinid genus Sundadanio (Ostariophysi: Cyprinidae) with descriptions of seven new species from Indonesia and Malaysia |journal=Ichthyological Exploration of Freshwaters |volume=22 |issue=3 |pages=251–288 }} At up to {{convert|2.3|cm|abbr=on}} in standard length they are very small,{{FishBase genus | genus = Sundadanio| month = August |year=2022 }} but still larger than their close relatives Paedocypris.{{cite journal|title=Evolution of miniaturization and the phylogenetic position of Paedocypris, comprising the world's smallest vertebrate|first=Lukas|last=Rüber|author2=Kottelat, Maurice |author3=Tan, Heok Hui |author4=Ng, Peter KL |author5= Britz, Ralf |journal=BMC Evolutionary Biology|year=2007|volume=7|pmid=17355618|pmc=1838906|page=38 |doi=10.1186/1471-2148-7-38 |doi-access=free |bibcode=2007BMCEE...7...38R }} Species of the two genera are often found together.