Songkhram medaka (Oryzias songkhramensis): how big does it get?

Oryzias songkhramensis is a medaka from the Songkhram River basin in northeastern Thailand, described by Magtoon in 2010 from Nong Khai Province. FishBase gives a maximum of 0.5 in SL, making it one of the smallest ricefishes. It belongs to the same Mekong group as O. mekongensis.

Taxonomy & naming

Magtoon described the species in 2010 from Ban Nong Phai, Ratanawapi, Nong Khai Province. The name refers to the Songkhram River, a Mekong tributary in northeastern Thailand and Laos.

Morphology

A tiny ricefish; FishBase gives a maximum of 0.5 in SL.

Habitat

Floodplain waters, ponds and rice paddies in the Songkhram basin and neighbouring parts of the Mekong in northeastern Thailand. FishBase describes it as a freshwater, pelagic fish.

Feeding

Diet has not been described for this species; small invertebrates and algae from the surface are typical of the genus.

Mating

Courtship has not been described.

Breeding

Breeding has not been documented in detail.

In the aquarium

Rarely seen in the trade. A planted tank at tropical temperatures with small live and frozen foods suits a fish of this size.

Conservation

The IUCN Red List assessed Oryzias songkhramensis as Data Deficient in 2011, meaning there is too little information to judge its extinction risk.

Common questions

Songkhram medaka (Oryzias songkhramensis): how big does it get?: Up to 0.5 in standard length (SL).
Songkhram medaka (Oryzias songkhramensis): where does it come from?: It is recorded from Thailand and Laos.

On a list: Nano fish

Related species compared · Oryzias

Species	Adult size	Temperature	pH	Hardness	IUCN
Songkhram medakaOryzias songkhramensisthis species	0.5 in SL	—	—	—	DD
Oryzias pectoralis	1 in SL	—	—	—	DD
Mekong medakaOryzias mekongensis	1 in TL	—	—	—	LC
Dwarf medakaOryzias minutillus	1 in TL	72–77 °F	pH 7.5–8.5	—	LC
Oryzias haugiangensis	1 in SL	—	—	—	DD
Oryzias hubbsi	1 in SL	—	—	—	NT
Oryzias uwai	0.5 in SL	—	—	—	DD
Oryzias chenglongensis	1 in SL	—	—	—	NE
Oryzias moramoensis	1 in SL	—	—	—	NE
Oryzias asinua	1 in SL	—	—	—	EN
Daisy's ricefishOryzias woworae	1 in SL	—	pH 6–7	—	EN
Soeroto's ricefishOryzias soerotoi	1 in SL	—	—	—	CR

Recorded ranges from each species’ own page; hardness is the tolerance its sources give, not a measurement of the water it lives in. See all 40 Oryzias species →

Sources

Naming authority: Oryzias songkhramensis in Eschmeyer’s Catalog of Fishes ↗

Last reviewed 2026-10-05.

How to cite

Aquarist Atlas (2026). Oryzias songkhramensis. Aquarist Atlas.https://www.aquaristatlas.com/ricefish/oryzias-songkhramensis/

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Where it has been recorded

1 georeferenced record (GBIF). Each point is a field observation or museum specimen — pan and zoom to explore where this species turns up. The coordinates come straight from GBIF and are often rounded or tied to the nearest town or river landing, so a dot can sit just beside the actual water rather than in it.

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