Taxonomy & naming
Weber described the species in 1894 in a different genus, and it now sits in Oryzias; the authority is therefore in parentheses. The name refers to Celebes, the older European name for Sulawesi. Because it is common and widespread, it has been the subject of many genetic and population studies of the Sulawesi radiation, and records labelled as O. celebensis in the older literature may include other southwestern Sulawesi species.
Morphology
A small, slender, translucent ricefish with a short, upturned mouth and a dorsal fin set far back. FishBase gives a maximum of 2 in TL. Males have larger dorsal and anal fins than females.
Habitat
Slow rivers, canals, ponds, rice fields and brackish waters of southwestern Sulawesi, around Makassar and the Maros River, the type locality, and parts of the surrounding lowlands. It tolerates a range of salinities. FishBase gives a pH range of 8.0 to 9.0, a hardness up to 16 dH and a temperature range of 22 to 30 C.
Feeding
A surface and mid-water feeder that takes small crustaceans, insect larvae and algae. In captivity it accepts small live foods and fine prepared foods.
Mating
Males display with spread fins and follow the female closely before spawning among plants.
Breeding
As in most Oryzias, females carry the egg cluster briefly and then deposit it on plants. FishBase reports it as a non-annual breeder that does not guard its eggs and hides them. Incubation time has not been published for this species.
In the aquarium
FishBase notes that it is difficult to maintain in aquaria. Keep a group in a planted tank with a lid, in hard, slightly alkaline water that may be lightly brackish, and feed small live and frozen foods. Keep it with other small, peaceful fish only.
Conservation
The IUCN Red List assessed Oryzias celebensis as Least Concern in 2018. It is widespread and common in lowland southwestern Sulawesi.