Oryzias haugiangensis: how big does it get?

Oryzias haugiangensis is a small ricefish from the lower Mekong, described by Roberts in 1998 from the Bassac River (Hau Giang) at Can Tho in Vietnam. FishBase gives a maximum of 1 in SL.

Taxonomy & naming

Roberts described the species in 1998, naming it for the Hau Giang, the Vietnamese name for the lower Bassac branch of the Mekong. It is one of several Mekong-basin ricefishes recognised since the 1980s.

Morphology

A small ricefish; FishBase gives a maximum of 1 in SL.

Habitat

Lower Mekong delta waters of Vietnam; FishBase says it is known only from the Mekong delta. The type locality is the Bassac River at Can Tho. It is a freshwater and brackish fish found in habitats strongly influenced by tides.

Feeding

Diet is not documented in the sources available.

Mating

Courtship has not been described.

Breeding

Breeding has not been documented.

In the aquarium

Not known in the aquarium trade.

Conservation

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

Common questions

Oryzias haugiangensis: how big does it get?: Up to 1 in standard length (SL).
Oryzias haugiangensis: where does it come from?: It is recorded from Vietnam.

On a list: Nano fish

Related species compared · Oryzias

Species	Adult size	Temperature	pH	Hardness	IUCN
Oryzias haugiangensisthis species	1 in SL	—	—	—	DD
Oryzias hubbsi	1 in SL	—	—	—	NT
Oryzias pectoralis	1 in SL	—	—	—	DD
Dwarf medakaOryzias minutillus	1 in TL	72–77 °F	pH 7.5–8.5	—	LC
Songkhram medakaOryzias songkhramensis	0.5 in SL	—	—	—	DD
Oryzias chenglongensis	1 in SL	—	—	—	NE
Oryzias moramoensis	1 in SL	—	—	—	NE
Oryzias asinua	1 in SL	—	—	—	EN
Oryzias uwai	0.5 in SL	—	—	—	DD
Daisy's ricefishOryzias woworae	1 in SL	—	pH 6–7	—	EN
Soeroto's ricefishOryzias soerotoi	1 in SL	—	—	—	CR
Oryzias wolasi	1 in SL	75–79 °F	—	—	DD

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 →

Also from the Lower Mekong

Sources

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

Last reviewed 2026-10-05.

How to cite

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

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Where it has been recorded

8 georeferenced records (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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