Environment: milieu / climate zone / depth range / distribution range
Freshwater; brackish; benthopelagic; pH range: 7.0 - 8.0; dH range: 9 - 19; amphidromous (Ref. 51243). Subtropical; 18°C - 24°C (Ref. 2060); 55°N - 10°N, 85°E - 105°E
Asia: Japan, Korea, China and Viet Nam. Reported from the middle Nam Theun, Mekong, Irrawaddy, Salween, Red River and Nanpangjiang in basins (Ref. 27732).
Size / Weight / Age
Maturity: Lm ?  range ? - ? cm
Max length : 4.0 cm SL male/unsexed; (Ref. 121523)
soft rays: 15 - 21;
Vertebrae: 30 - 31. Meristic characters mainly from Nam Theun, Laos sample only (Ref. 27658). Scale count refers to the scales in longitudinal row (Ref. 41299).
Adults occur in ponds, marshes, paddy fields and small flows of plains (Ref. 41299). They prefer slow-moving streams. Inhabit mainly waters of lowlands and brackish water, and also known to inhabit tide pools of coasts of certain regions in Japan and Korea. They can withstand a wide range of salinity (Ref. 58933). Omnivorous (Ref. 58933). For indoor culture, a diluted sea water is rather better than the freshwater , and the use of a balanced salt solution is recommended, if the tap water proves to be unsuitable (Ref. 58933). Used in experimental research (Ref. 4537). Non-annual breeders. Are easy to maintain in the aquarium (Ref. 27139). A fluorescent ornamental variety (genetically modified fish), a product of fluorescent protein extracted from jellyfish and attaching to DNA in embryonic fish of this is now being sold in the aquarium trade (Ref. 48573).
Carries eggs for some time before deposition (Ref. 7471). Oocytes mature at night followed by ovulation at dawn (Ref. 58942).
Roberts, T.R., 1998. Systematic observations on tropical Asian medakas or ricefishes of the genus Oryzias, with descriptions of four new species. Ichthyol. Res. 45(3):213-224. (Ref. 27658)
IUCN Red List Status (Ref. 126983)
Threat to humans
Fisheries: of no interest; aquarium: commercial
Estimates based on models
Phylogenetic diversity index (Ref. 82804
= 0.5000 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.00479 (0.00190 - 0.01207), b=3.13 (2.91 - 3.35), in cm total length, based on LWR estimates for this (Sub)family-body shape (Ref. 93245
Trophic level (Ref. 69278
): 3.4 ±0.45 se; based on food items.
Generation time: 0.3 ( na - na) years. Estimated as median ln(3)/K based on 1 growth studies.
Resilience (Ref. 120179
): Low, minimum population doubling time 4.5 - 14 years (tm<1; Fec=40).
Fishing Vulnerability (Ref. 59153
): Low vulnerability (10 of 100).