Home / Fishes / Ricefish, halfbeaks, needlefish / Oryzias wolasi
No federal permit to keepOryzias wolasi
Oryzias wolasi
Fishes › Ricefish, halfbeaks, needlefish (Beloniformes) › Adrianichthyidae (Ricefish and medaka)
Care follows the ricefish and medaka guide below.
Care at a glance
Species-specific aquarium care
- Tank: At least 24 in long and 12 in front to back for one adult (adults commonly reach about 1.1 in / 2.86 cm).
- Water: Freshwater.
- Temperature: 75–79°F (range recorded for this species).
- Layout: Uses both the bottom and open water: give open swimming space plus cover near the substrate.
Calculated from this species' own FishBase record: tank size from its typical adult length and swimming zone, water values from its recorded ranges. The group guide below fills in general care.
Care guide
Species care notes
- Tank: a base of at least 18 × 12 in (roughly 11 US gallons); space needed is rated “modest tank”.
- Water: a fairly wide range, from slightly acidic to slightly alkaline, 73–81 °F, pH 7–8, 10–20 dGH.
- Behaviour: temperament peaceful; a shoaling fish best kept in a group of six or more; suited to a community tank.
- Difficulty: Easy (Seriously Fish rating).
Short excerpts from the species profile:
- Setup: “Best maintained in a heavily planted set-up, ideally with a dark substrate, patches of dense vegetation, and some open areas.”
- Diet: “Unfussy but must be provided with foods of a suitable size.”
- Tankmates: “Very peaceful but doesn't make an ideal addition to many communities due to its small size.”
- Breeding: “Quite easy to breed and fairly prolific, with females capable of producing batches of eggs every few days or even on a daily basis when in good condition.”
From the Seriously Fish profile for this species, which has the full habitat, maintenance, diet, behaviour and breeding write-up 167
Ricefish and medaka
Applies to most species in this group. Habitat: Ricefish occupy Asian rice paddies and other shallow fresh/brackish habitats, while several listed Sulawesi species inhabit ancient freshwater lakes (medaka, sulawesi). Individual species can differ, so compare with the species numbers above and the linked sources.
Housing & setup
- O. latipes: at least a 45 × 30 cm aquarium footprint (medaka).
- Most Sulawesi ricefish: at least 45 L and 0.16 square metres of floor area; species over 60 mm need 120 L and 0.4 square metres (sulawesi).
- O. nigrimas needs open swimming space and a tank at least 80 cm long (sulawesi).
- For medaka provide dark substrate, dense plants, surface vegetation and open patches (medaka).
- Determine locality and salinity before setting up wild-origin fish (medaka).
Diet
- Suitably sized quality flakes or granules (medaka).
- Live/frozen Daphnia and Artemia (medaka).
- Finely chopped bloodworms (medaka).
Social life
- Medaka are more confident in groups of eight or more; separate Oryzias species for breeding because hybridization is possible (medaka).
Health watch
- Ammonia toxicity from inadequate biofiltration (fish_health).
- Parasitic skin and gill infections (fish_health).
- Nutritional deficiencies from unsuitable diets (fish_health).
Understanding the animal
In the wild
In the wild
From this species’ own FishBase record (habitat, bottom type, water and breeding data), not its family. Good care copies these conditions.1
| Where it lives | Lives in freshwater. Uses both the bottom and open water. Inhabits slow to swift-flowing freshwater stream with a substrate of mud, small rocks, and plant debris with emergent grasses and a shore of mud, rocks and grass. Also found in a relatively cool (24°C), swift-flowing stream along Sumbersari Falls and a warmer (26°C), springfed coastal stream. |
| Water it lives in | Freshwater, 75–79 °F (24–26 °C). |
| Climate | Tropical climate. |
What this means for care
- Keep water within its wild range, 75–79 °F.
From the sources
From the sources
Quoted from the matching sections of reputable sources for this exact species. Specialist databases are used first; Wikipedia (community-edited, CC BY-SA 4.0) only fills gaps. Other sources are short credited quotes.
| Where it lives | Home ranges Population dynamics Growth parameters Max. ages / sizes Length-weight rel. Length-frequencies Mass conversion Recruitment Abundance Life cycle Reproduction Maturity Maturity/Gills rel. — FishBase |
| Biology | Inhabits slow to swift-flowing freshwater stream with a substrate of mud, small rocks, and plant debris with emergent grasses and a shore of mud, rocks and grass. Also found in a relatively cool (24°C), swift-flowing stream along Sumbersari Falls and a warmer (26°C), springfed coastal stream. — FishBase |
Data and studies
The numbers
The numbers
Each bar is what one source reports. Where several sources weigh in, the dashed gold band marks their average.
Adult length
Maximum recorded length. Measured as standard length (snout to the base of the tail, not counting the tail fin). Fish in home aquariums often stay smaller than wild records.
Water temperature
Range the species tolerates in nature; aim for the middle.
pH
Water hardness
Minimum tank footprint
Seriously Fish recommends a tank base of at least 18 × 12 in (about 11 US gallons).
Sources for this sheet
- FishBase (Froese & Pauly, eds.), version 24.07 Peer-reviewed researchThe global scientific database on fishes, maintained by a consortium of research institutions; every value is referenced.
- Seriously Fish species profiles Experienced keeper or breederLong-running aquarium reference written and peer-checked by experienced fishkeepers and ichthyologists; each profile covers habitat, tank size, water, diet, behaviour and breeding.
- Seriously Fish: Oryzias latipes Experienced keeper or breederAdded in the 2026 source-checked care-guide review.
- Schwarzer et al. (2026): Sulawesi ricefish biology and aquarium husbandry, Bulletin of Fish Biology Peer-reviewed researchAdded in the 2026 source-checked care-guide review.
- Merck Veterinary Manual: Disorders and Diseases of Fish Zoo, university or veterinaryAdded in the 2026 source-checked care-guide review.
- Merck Veterinary Manual: Management of Aquarium Fish Zoo, university or veterinaryAdded in the 2026 source-checked care-guide review.
