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No federal permit to keepGreen Plakad
Betta mahachaiensis
Fishes › Gouramis, bettas, snakeheads (Anabantiformes) › Osphronemidae (Gouramis and bettas)
Betta mahachaiensis is a species of bubble-nesting betta native to Thailand, where it occurs naturally near the Gulf of Thailand.

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 1.7 in / 4.37 cm).
- Water: Freshwater (tolerates brackish).
- pH: 6.87–7.8.
- Layout: Uses both the bottom and open water: give open swimming space plus cover near the substrate.
- Availability: Rarely or never seen in the aquarium trade; expect to source it from specialists or not at all.
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, 72–82 °F, pH 7–8.5, 5–20 dGH.
- Behaviour: temperament species tank; in a pair; not a community fish.
- Difficulty: Moderate (Seriously Fish rating).
Short excerpts from the species profile:
- Setup: “Can be maintained in medium-hard to hard fresh or slightly brackish conditions, and does best in a well-planted, shady tank with plenty of surface cover in the form of tall stem or floating plants.”
- Diet: “Likely to prey on insects and other small invertebrates/zooplankton in nature.”
- Tankmates: “Not recommended for the standard community set-up for reasons already touched upon.”
From the Seriously Fish profile for this species, which has the full habitat, maintenance, diet, behaviour and breeding write-up 167
Bettas (fighting fish)
Applies to most species in this group. Habitat: Shallow rice paddies and marshes. Individual species can differ, so compare with the species numbers above and the linked sources.
Housing & setup
- A heated, filtered tank of at least 5 gallons, with gentle flow and plants.
- Domestic B. splendens should generally be maintained alone. Other Betta species need their own compatibility plan; B. imbellis can be maintained as a pair with adequate cover.
Diet
- Betta pellets plus frozen foods.
Social life
- Use species-specific social housing: B. splendens alone under the detailed Seriously Fish recommendation; B. imbellis may be housed as a compatible pair.
Health watch
- Fin rot in dirty water; never keep bettas in tiny unheated bowls.
Understanding the animal
About this animal
About this animal
It is typically seen in stagnant waters in swamps, pools, and ponds. The species can be found in brackish waters, with salinity levels between 1.1 and 10.6 parts per thousand.
Quoted from the Wikipedia article “Betta mahachaiensis” (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 and brackish water. Uses both the bottom and open water. Encountered in nipa palm (Nypa fruticans) swamps, especially in the water-holding phytotelma of the palm bract, which the pair use for bubble-nest building, courtship, and hatching of fry. |
| Water it lives in | Freshwater / brackish water, pH 6.87–7.8. |
| Climate | Tropical climate. |
| Behavior to plan for | Breeding: clutch tenders, biparental parental care. |
What this means for care
- It tolerates or needs brackish water; check salinity needs before setup.
- Parents guard eggs or young, so expect territorial behavior when breeding.
Native climate (measured)
Native climate (measured)
| Warm-season highs | about 94°F (up to 94°F in the hottest sampled areas) |
| Cool-season lows | about 69°F (down to 69°F in the coldest sampled areas) |
| Average temperature | 81–83°F across sampled records |
| Relative humidity | 73–74% on average (driest month about 67%) |
| Rainfall | about 1222 mm a year, with strong wet and dry seasons |
Measured at 6 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.
| Overview | Betta mahachaiensis is a species of bubble-nesting betta native to Thailand, where it occurs naturally near the Gulf of Thailand. It is typically seen in stagnant waters in swamps, pools, and ponds. The species can be found in brackish waters, with salinity levels between 1.1 and 10.6 parts per thousand. Betta mahachaiensis is capable of living in both fresh water and brackish water, a trait unique among fish in the genus Betta. — Wikipedia (community-edited) |
| 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 | Facultative air-breathing; Encountered in nipa palm ( Nypa fruticans ) swamps, especially in the water-holding phytotelma of the palm bract, which the pair use for bubble-nest building, courtship, and hatching of fry. — 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; aim for the middle.
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.
- Merck Veterinary Manual: Management of aquarium fish Zoo, university or veterinaryThe Merck Veterinary Manual: a standard veterinary reference written and reviewed by veterinary specialists.
- Merck Veterinary Manual: Types and features of aquatic systems Zoo, university or veterinaryThe Merck Veterinary Manual: a standard veterinary reference written and reviewed by veterinary specialists.
- Merck Veterinary Manual: Nutritional diseases of fish Zoo, university or veterinaryThe Merck Veterinary Manual: a standard veterinary reference written and reviewed by veterinary specialists.
- Seriously Fish — Betta splendens Zoo, university or veterinaryAdded in the 2026 source-checked care-guide review.
- Seriously Fish — Betta imbellis 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.
- iNaturalist (captive observations) Community referenceCommunity observation platform run by the California Academy of Sciences and National Geographic; observations marked captive show animals living in homes, zoos and aquariums.
