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No federal permit to keepPowder-blue panchax
Pachypanchax omalonotus
Fishes › Killifish and livebearers (Cyprinodontiformes) › Aplocheilidae (Panchax killifish)
Pachypanchax omalonotus, the powder-blue panchax, is a species of Aplocheilid killifish endemic to Madagascar where it is found on the island of Nosy Be and in the Sambirano River basin and adjacent streams on the mainland.
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 3.7 in / 9.5 cm).
- Water: Freshwater.
- Temperature: 72–82°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 35 × 12 in (roughly 21 US gallons); space needed is rated “large tank”.
- Water: a fairly wide range, from slightly acidic to slightly alkaline, 68–82 °F, pH 6–7.5, 2–15 dGH.
- Behaviour: temperament peaceful; a shoaling fish best kept in a group of six or more; not a community fish.
- Difficulty: Moderate (Seriously Fish rating).
Short excerpts from the species profile:
- Diet: “The faeces of wild fish has been observed to contain both aquatic and terrestrial insects, suggesting it feeds both at the water surface and from the substrate.”
- Tankmates: “Relatively peaceful although much smaller fishes are likely to be predated on, and given its conservation status it's perhaps best maintained alone.”
- Breeding: “If conditions are suitable this species is not difficult to breed and will deposit its eggs among live plants, aquatic mosses, synthetic mops, etc.”
From the Seriously Fish profile for this species, which has the full habitat, maintenance, diet, behaviour and breeding write-up 167
Panchax killifish
Applies to most species in this group. Habitat: Aplocheilus inhabit vegetated Asian streams, swamps and rice paddies, while Pachypanchax occur in Madagascar and Seychelles freshwater habitats (lineatus, playfairii). Individual species can differ, so compare with the species numbers above and the linked sources.
Housing & setup
- For A. lineatus use at least 75 × 30 × 30 cm, approximately 68 L (lineatus).
- Fit a close-fitting lid to prevent Aplocheilus jumping (lineatus).
- Provide dim lighting, floating plants and dense planted refuges (lineatus).
- Arrange wood and rocks into hiding places, especially for subordinate fish (lineatus).
Diet
- Quality dried food sized to the fish (lineatus, playfairii).
- Live or frozen Daphnia and bloodworms (playfairii).
- Gut-loaded wingless fruit flies or tiny crickets for Pachypanchax (playfairii).
Social life
- Keep only tankmates too large to swallow; male aggression requires space and refuges, and species tanks are preferable for conservation breeding (lineatus, playfairii).
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
About this animal
About this animal
Its natural habitat is rivers.
Quoted from the Wikipedia article “Pachypanchax omalonotus” (CC BY-SA 4.0) 174
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. Occurs in brooks and small rivers, mostly in quiet parts. |
| Water it lives in | Freshwater, 72–82 °F (22–28 °C). |
| Climate | Tropical climate. |
| Behavior to plan for | Breeding: open water/substratum egg scatterers. |
What this means for care
- Keep water within its wild range, 72–82 °F.
Native climate (measured)
Native climate (measured)
| Warm-season highs | about 89°F (up to 89°F in the hottest sampled areas) |
| Cool-season lows | about 65°F (down to 61°F in the coldest sampled areas) |
| Average temperature | 76–79°F across sampled records |
| Relative humidity | 73–74% on average (driest month about 66%) |
| Rainfall | about 1894 mm a year, with strong wet and dry seasons |
Measured at 5 wild occurrence records sampled against WorldClim 2.1 climate data (1970–2000 averages). Air conditions in the range are ecological context, not enclosure settings: microhabitats such as burrows, leaf litter or basking rocks can be cooler, warmer or more humid.
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 | Occurs in brooks and small rivers, mostly in quiet parts. Not a seasonal killifish. Is difficult to maintain in aquarium; prefers aquaria with rocks, plants and driftwood. — 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 total length. 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 35 × 12 in (about 21 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: Aplocheilus lineatus Experienced keeper or breederAdded in the 2026 source-checked care-guide review.
- Seriously Fish: Pachypanchax playfairii Experienced keeper or breederAdded 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.
- Wikipedia (species article) Community referenceFree encyclopedia; useful overviews with their own citations. Intro text is quoted under CC BY-SA 4.0.
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